How to do a marine fish freshwater dip for prophylaxis and as a treatment for ich

With an established marine aquarium, disease prevention is a mandatory task. The typical method to prevent the introduction of diseases is to quarantine new livestock for 4 weeks in a dedicated quarantine tank. This is a tank set aside for this purpose and typically is set up without invertebrates so that medication may be administered if necessary.

However not everyone has the resources to maintain a quarantine tank, and some livestock is too large for any but the most extreme sized quarantines. Additionally you may have issues with your livestock within the display tank picking up a disease or parasite.  This is due to a weakened immune system cause by environmental factors.

The puffer shown below has picked up an ich infection due to ammonia poisoning. Note the white cysts on his skin and fins. Puffers are especially susceptible as they have no scales. This also means that most copper based ich medications can be fatal to them.

For these issues the solution is to do a freshwater dip. Fish can osmo-regulate much more effectively than invertebrates can. This means a marine fish can withstand freshwater conditions far longer than most parasites can without long term damage or even ill effects. The freshwater dip is so efficacious that it is standard procedure for most of the larger marine importers.

Material needed

  • Baking soda (calcium carbonate)
  • High range pH test kit
  • RO/DI water
  • Air pump, tubing and airstone
  • Container for the dip (tupperware is my preference)
  • Methylene Blue (optional)
  • Large container containing mixed saltwater from the display (optional)
I first will aerate the RO/DI water for at least 3 hours using the air pump and an airstone. This will help stabilize the pH of the water.
I then float the RO/DI water in the display tank to equalize the temperature, this could also be accomplished using a heater, but may melt the container if care is not taken.
I’ll take a sample of the display tank and measure the pH of the salt water in the tank. I’ll use this sample to match the pH of the RO/DI mixture against.
Once the temperature is equalized I will then slowly mix in baking soda one tablespoon at a time to match the pH of the display tank. I let the RO/DI mix sit for 15 minutes between measurements.

It is important to match the pH as closely as possible. This experience will be stressful on the livestock regardless, but it is best to minimize the difference in water conditions. Once the pH is as closely matched as possible you can then add the Methylene Blue (optional).

Once the pH is matched I’ll then net the fish and place it in the RO/DI mixture. I’ll closely observe the fish to ensure it isn’t too distressed. Leave the fish in the RO/DI mixture no longer than 5 minutes! Once the fish starts trying to leap from the container, starts thrashing or breathing very heavily (more than 80 breaths a minute) remove it from the RO/DI mixture and either return it to the display, or if you used the Methylene Blue place it in the rinse container. If the fish is added to the rinse container, let it sit in that container for 2-5 minutes to fully rinse the Methylene Blue traces from the fish.

As you can see with the images below it can be a stressful experience for the fish! It also can be a lifesaving measure however, so it definitively beats the alternative!

The dangers of ammonia based products and marine aquariums

I recently had a near miss with my puffer. The landlord decided that the house needed cleaning and mopped the floor using Pine-Sol. Despite my repeated warnings to the contrary it was assumed that the ammonia on the floor couldn’t possibly be dangerous.

I come home to find the porcupine puffer in dire condition. His color was very dark and ashy and he was laying on the sand unmoving. When I tested the water I read .5ppm (parts per million). This small amount is enough to threaten saltwater fish, and puffers are even more susceptible as they have no scales.

A .5ppm level indicates that there was less ammonia than would fit in a bottle cap in the system, yet this level can be fatal. The ammonia entered the system from the surface of the tank from evaporated ammonia. Ammonia is hygroscopic in nature, which means it has a high affinity for water.

I did a crash water change of almost 30 gallons, enough to bring the levels down to .10ppm, and below the fatal level. This is a small enough amount to allow the bacteria in the system to convert it to nitrites and then nitrates.

It is important to avoid any ammonia based cleaners in the vicinity of your tank! In my case I’m banning them from the house, not just the living room area in the future.

DIY low tech automatic top off (ATO) for marine aquariums with sump

One of the issues a saltwater aquarist has to contend with is loss of water through evaporation. As most marine systems employ much higher wattage lighting than freshwater tanks, the rate of loss can be surprising. As an example, my 135 gallon tank can lose up to 1.5 gallons a day in the summer!

Another issue that especially plagues smaller tanks is the change in salinity caused by this loss. As only pure water is lost, the salt remains in the tank, and salinity increases. The loss of 1 gallon of water in a 15 gallon nano reef can shift the specific gravity (SG) from 1.024 to 1.027. This can be stressful on corals and livestock alike.

My (very) low tech approach to this is to use the same float valve that is used within reverse osmosis systems. I purchased this specific float valve from eBay for $9 plus shipping.

Materials Needed

  • 1/4” air-line tubing ($10)
  • 1/4” valve (($1.25)
  • Scrap plexi-glass/acrylic/plastic (free?)
  • Float valve ($9)
  • Nylon hardware ($1.50)
  • Water container/ 5 gallon bucket/etc. ($3-$15)

Tools needed

  • Drill
  • 5/8” drill bit
  • 1/4” drill bit
  • superglue

The first step is to remove the metal hardware in the float valve and replace it with nylon. Drill out the old screw with a 1/8” bit. Thread the new hardware in and tighten it down. You could also simply glue the pieces together instead, and lose the ability to adjust the level. I purchased the nylon hardware at my local Home Depot for roughly $1.50

You then take a scrap of acrylic/plexiglass/plastic and cut it to roughly 2”x4” in size. This is then bent into a 90 degree angle using a heat gun. The plastic can be any sufficiently robust material available. The heat gun can be replaced with a hair-dryer as well, assuming you have patience. The hair dryer adds considerable time to the job.

You then drill out a 5/8” hole into a 5 gallon bucket, and plumb it with a 1/4” line quick release fitting. This will be the RO/DI water reservoir. It could be substituted for a 5 gallon water carrier easily, especially because they have a nipple available to use for this purpose.

5 gallon bucket with plumbed quick release fitting


5 gallon water jug with threaded fitting on top of pic


The float valve is then inserted into the drilled hole and screwed down tightly. Insert about 8” of 1/4” line into the float valve and then a 1/4” valve. Then apply as small quantity of superglue to the vertical face of the plastic (it helps if it is scuffed up somewhat). The angle plastic is then placed at the correct height inside the sump.

Run the 1/4” tubing back to where you placed your reservoir and cut it to length. Fill the reservoir at this point, and find the free end of the tubing. Suck on the tubing until all the air has been displaced, then connect it to the check valve. Turn on the check valve at this point and you’re done!

If you are a belt and suspenders sort of person you can add another float valve into the reservoir itself. This valve will be installed upside down, and will use gravity to close the valve. This will prevent the line to the sump from sucking air into it if the reservoir is empty. Not really worth the extra effort in my opinion, but if you are likely to let the reservoir run dry it’s not a bad idea.

Images of this setup in operation below.

The float valve glued in place



The ball valve to shut off flow



Wider angle shot of float valve in operation (note the “max fill” marking)

Electrical safety for Marine aquariums

There are a few hazards associated with saltwater tanks that aren’t present in freshwater set-ups. One of them involves the conductivity of saltwater.

There are two easy steps that can prevent injury, one of which doesn’t even cost a dime!

Install a GFCI outlet

This step should really be done before setting up the tank, but you may be able to retro-fit your outlets depending on clearance or use a GFCI power cord extension. the outlets can be purchased as cheaply as $9, and the extensions go for $15 typically.

A GFCI (Ground Fault Circuit Interrupter) functions differently than a breaker or fuse. Fuses and breakers have a limit on current flow that has to be exceeded before they trip or blow. A GFCI outlet instead uses the presence of as little as 5 milliamps of current flow from the hot line to ground to trip. It can open the circuit in as little time as 30 milliseconds, fast enough to prevent fatal injury in most cases.

Add drip loops to power cords

Once the tank has been set up and the location of power-heads has been decided be sure and put some drip-loops into your cords. These are simply loops of cable that provide an easy path for water to drip from. This prevents water from running into your outlets. As saltwater is both corrosive and conductive it is best to keep it out of your electrical components.

Drip acclimation of aquarium livestock

One of the more contentious topics in fish-keeping is how to acclimate your newly purchased fish for the tank.

The method I prefer for both freshwater and marine fish is drip acclimation. Note that there are a few caveats to this method; if the fish have spent many hours in a shipping bag it is not advisable. As ammonia toxicity decreases with pH it shouldn’t be used because the pH will rapidly climb when the bag is open and the water mixes. This is likely harm the fish as the toxicity of the ammonia spikes.

Drip acclimation can be done as elegantly or as simply as you care to do it. The simplest method uses 1/4” tubing and a black metal paperclip. The paperclip is used to crimp the tubing and reduce flow.

Or you can use the same tubing with a suction cup to hold the tubing in place, and a valve to adjust flow. For the more ambitious you can even float the acclimation container in the tank and use a pump for delivery. This will speed up the temperature equalization, though not strictly necessary as the ingress of water from the display tank will do the same.

The use of a valve allows for finer control of drip speed than the metal clip method of crimping the tubing. It is inexpensive to purchase valves intended for use in sprinkler drip systems for the local hardware store as well.

Quite simply drip acclimation is the process of slowly adding water from the tank to the container holding the livestock and the shipping water. This process lets the livestock gradually adjust to the difference between the two. There are always slight differences in mineral content, pH and nitrates as well as the presence of trace materials between two tanks.

I prefer to run my acclimation at roughly a drop per second. Once I’ve doubled the amount of water I’ll scoop out a cupful and continue the process. I’ll spend up to an hour with fragile species, but with hardier fish such as Blue/Green Chromis I’ll run the drip for 30 minutes.

Once the time frame allotted has passed I then net the fish from the container and evert the net into the water. It is advisable to not empty the shipping water into your system as you can introduce undesirable hitchhikers that way. In a marine tank you could conceivably introduce aiptasia or mojano anemones via small free floating juveniles.

With a saltwater system a further step is required if you don’t have a quarantine tank. I strongly recommend using a 4 to 6 week quarantine, but as this is an expensive hobby your resources may not stretch that far.

The final step for a non-quarantine marine system is a freshwater dip. This s a topic worthy of it’s own post so will have to wait until I have some new livestock to demonstrate with.

A short clip of my DIY LED moonlighting in action, and a blue/green chromis making a guest appearance.

Acclimating a mail-order cleanup crew

Acclimating new arrivals via mail order is a slightly different process than acclimating livestock from your LFS (Local Fish Store). Additionally there are some differences with the types of livestock purchased. In this post I’ll be showing how to acclimate a clean-up crew composed solely of snails. The process would be the same if hermits were included as well as most invertebrates.

Most species utilized for aquarium cleaning are intertidal inhabitants. This means they can accommodate changes in salinity and to an extent pH changes much better than most other livestock. So we’ll be more concerned with matching temperature than we will water conditions.

Rather than drip acclimate into a bucket we will float them in the bag they came in; be sure and leave the bag closed! While normally you would open the mouth of the bag for surface area for oxygen exchange, we want to avoid this; while the bag is open the CO2 in the water will be dissipating and the pH will rise.

The water the animals were shipped in has a low pH due to the raised CO2 levels from carbonic acid. This is actually beneficial as it makes the ammonia less toxic. If I were to add water from the display tank, the pH would rise quickly and it would make the ammonia much more toxic. Ammonia toxicity is directly related to pH levels.  I’m more likely to lose livestock via ammonia poisoning than I am from the pH and salinity changes. The most important thing is to get the temp matched and get them out of the water they arrived in.

I had my wife bring the package into the house in a warmed area as soon as it arrived. This will bring the temperature up somewhat, and speed the process for me. However I assume most of you will be at the mercy of your employer and the postman and will likely have the package in the weather for a time. No worries though, these are all exothermic animals and as long as the temp doesn’t approach freezing they’ll survive. For those of you in colder climes I’d advise waiting until spring for your order, or ship overnight with someone ready to receive the package for you.  Reefcleaners does ship with a heat pack as shown below.

This particular order is well packed and insulated. Due to the care taken with shipping I expect few losses among these animals. This illustrates an important point too, while I may have spent a bit more by going through reefcleaners.org (well actually I didn’t) I’ll keep more of my livestock than otherwise. Avoid the false economy of buying in larger lots from a wholesaler who cuts corners. They won’t have a high survival percentage, and you will find out why your LFS sells Blue/Green Chromis for $5 and buys them for $1. It’s the 50% mortality rate.

Another thing to note is that I won’t be quarantining these animals. The tank volume required to feed this many snails in a quarantine would be the same as the display tank! I’ll also avoid doing a pH matched freshwater dip as well. These animals are a bit stressed from their trip to San Diego from Florida.

After about 20 minutes have passed I’ll net the snails and put them in the display tank. Due to the puffer I’ll try and put them in an area away from his normal hangouts. They should be placed in a visible area though. Any snail that loses it’s operculum (the trapdoor that closes the shell) is dead, and any that don’t move after 24 hours are likely dead as well. It is important to get them out as soon as possible. There is already an increase in bio-load, and the addition of ammonia from decaying snails could induce a mini-cycle and endanger the fish. Be sure and dispose of the water they came in though, as this will minimize the risks of introducing parasites that could harm your fish.

I’ll continue to check on them for another week or so. More may have been over-stressed and weakened enough not to survive more than a few days. The Cerith snails are an exception though; they can go dormant and estivate for several days.

While the acclimation process has been completed there are a few ethical points to make here. The large one is sustainability. While these animals were sourced from a vendor who farms their own livestock, most marine animals are wild caught. They suffer terrible conditions during shipment due to the low profit margin, and have obscene mortality rates. As many as 4 out of 5 anemones don’t survive more than a month as an example.

Another point to be made regards dumping unwanted livestock into your local ocean. The animals used in marine tanks are tropical species. That means dumping a blue leg hermit from the Caribbean into the Pacific is a bad idea. It can introduce diseases that the local animals have no resistance to, and the hermit will die regardless due to being out of it’s preferred habitat. This is actually the best case scenario. For example, Caluerpa is now illegal to have in California as un-thinking hobbyists have allowed it into the wild.  It has rapidly become a problem by displacing native species.

So be sure to enjoy your tank, but be responsible as well. I hope that my step-children can enjoy this hobby as much as I do in the future.

A short pic of my marine tank during a huge cyano bloom. I have a booster pack of cleaners coming from www.reefcleaners.org

These guys are flat out the best source for clean-up crews. They harvest the animals themselves and do it sustainably too. Tell John that Ian sentcha’ to give me a referral bonus too.

DIY CO2 system

This is a short write up of my DIY low tech CO2 system for a planted aquarium. It has been running for about 2 years now without issue.

Parts list

  • 1/4” airline tubing
  • 2X 2 liter bottles
  • 1X 12 ounce bottle
  • 4X 1/4” fittings
  • 1X 1/4” gang valve
  • 1X bubble counter (optional)
  • 1X diffuser

Equipment List

  • 5/16” drill bit
  • electric drill
  • 2 part epoxy

Misc. materials needed

  • Yeast (bakers)
  • Sugar
  • Aspirin (optional)

The formula for the yeast mix is simple. I use a pinch of bakers yeast (Red Star in my case) mixed into warm water at 100F to 115F, or roughly hot enough to be uncomfortable but not burn. I’ll let it sit for 5 minutes then stir in 3/4 cup of sugar. I’ll then leave it uncovered for about an hour to let he yeast fully activate. I then add 1/2 of an aspirin (generic of course) and attach the bottle to the system.

The aspirin is optional, but helps keep bacterial blooms in check and allows you a bit more leeway when cleaning the bottles before reuse.

The tubing being used is the cheap airline tubing available at a hardware store. Over time the CO2 and ambient ultraviolet degrades it and it will need to be replaced. I change my tubing out yearly. You can use the more expensive CO2 rated tubing, but as the airline stuff is so cheap the ROI on the higher quality tubing is about 7 years.

I use a cheap gang valve to enable me to pull one bottle from the system while retaining pressure. This keeps the system running while I clean and fill the bottle. 

To build the system I’ll first drill a 5/16” hole in the caps for both the 2 liter bottles, and drill 2 5/16” holes in the 12 oz bottle. The 1/4” fittings are squeezed into the holes, then potted thoroughly with epoxy. Let them sit and cure for at least 24 hours before use. I find the white epoxy works better than the clear and is more resistant to degrading from exposure.

I use Pepsi bottles as the caps are constructed without a separate seal and have a molded lip used to retain pressure instead. The actual bottle being used isn’t important beyond aesthetics as most can withstand up to 100 psi.

Once the epoxy is dried the system can be set up. Attach a short piece of tubing (3” or so) to the inside of the cap used for the 12 oz. bottle going to the input side. This will act as a trap for vapor and prevent any accident addition of the yeast mixture into the tank. I used an old air diffuser with the stone broken off to weight the end to keep the tubing straight. While this bottle isn’t necessary, if your system ever dumps you’ll be glad you have it as it will catch the yeast sugar mixture before it pollutes the tank.

I’d advise filling only one bottle at first, then filling the second the following week. At this point a bottle can be recharged weekly and keep a decent level of CO2 in the system.

I’m using a knock-of glass/ceramic diffuser on my system. Note that it may take a day or three to begin seeing bubbles from this style diffuser. They are made to run on systems of +20 psi and the DIY rigs rarely reach that pressure. Be patient however and you will see bubbles from the diffuser in time.

How to quiet a noisy HOB filter

Many new HOB filters (Hang On Back) that come with tank sets are very noisy when first used. It can take weeks for a bio-film to build up on the impeller and quiet the rattle. In some cases, especially with the cheaper models the tank never does stop being noticeably noisy.

The following post shows how to quiet your HOB filter for nothing more than the cost of a small jar of Vaseline.

Note the ingredient, no additives, menthol etc. added. You could possibly even use generic lip-balm if it has nothing more than petroleum jelly. It is inert for all practical purposes in a freshwater tank. I have no experience using this method on a marine system, so use at your own risk in a saltwater tank.

The first step is to pull the lift tube from the u-tube. If this is a filter that’s been running a while it is also a good opportunity to give it a good scrub.

Once the lift tube is out the u-tube will pull out vertically, see the side view pic below to illustrate how the u-tube seats.

Simply pull upwards steadily until the u-tube comes free.

Once the u-tube has been removed you should see an impeller, they are typically green or white, but the color may vary and is unimportant.

Use a pair of needle-nose pliers, long tweezers or even chopsticks, pull the impeller from the housing. Pull straight up, but expect a bit of resistance from the magnet of the impeller and the drive coil.

Once the impeller is free wipe it down and remove any debris. this is not necessary with a new filter unit.

Using a small amount of Vaseline apply it evenly to the magnetic cylinder of the impeller.

Using the pliers, tweezers or chopsticks place the impeller back into the drive housing. Then, ensuring it is lined up, replace the u-tube over the impeller. There should be an alignment post or slot on the HOB filters body. Once it’s lined up it should seat easily and solidly.

Note the flow control on the u-tube. On occasion this will generate noise as bubbles of air slip by the seal and move through the impeller. This can sound like a can full of rocks if severe. By pulling the adjuster and liberally applying Vaseline around the seal this problem can be fixed as well.

Replace the lift tube. mount the filter on the tank and be sure to prime it before powering it up. A cup full of water should be enough to get it started.

You should now have a whisper quiet filter without spending a fortune on a high end brand.