Backyard Aquaponics
A place to discuss aquaponics

Trouble

I came home to find my fish near the surface and not responding much to me. I tested the nitrites and found that they were off the chart!

So I proceded to change 50% of the water and took another reading and I could not tell that it had changed. So I waited 20 min and did another 50% water change. Tested again and still the same results; off the chart or at the high end of the test. That did not seem possible so I got out my new nitrite test kit and tested again just in case it was a test problem. The new test gave the same results.

Now, I would think it is impossible to have anything in the water after two back to back 50% water changes. Has anyone else experienced anything similar?

The only thing I can think of that might taint the results is the fact that while cleaning I found a bottle of starter bacteria mix and before I threw it away I could not help but pour some into the new FSB bio-filter. Even so, I don't understand why the nitrite test is reading off the chart. So, I thought perhaps its all the food bits rotting in the gravel. I removed most of the gravel from the bottom of the tank stirring up a nasty fog of particles in the process..

Any ideas? If the nitrites are not that high then I may have over reacted and changed to much water and removed gravel for no reason. The fish are acting normal today; swimming and responding normally, but the test still shows lethal amounts of nitites. I have a bubbler, the returning water fall from the FBS, and a small venturi power head all pumping air into the tank. It could be that the bacterial mix I added had enough sugar in it to make the bacteria breed like mad and they could have used up most of the oxygen.

Salt will mitigate nitrite toxicity DanD ....

How much salt per gallon? (and is that an Imperial gallon)

Not on my (computer) system at the moment DanD... so can't convert....

But we use 3ppt as a rule.... this rate will impact some plants more than others though.....

How can salt help with nitrites BTW? What does it do?

Well, on the up side of things the insulations guys finally got out and sprayed the insulation in!
IT took them like 30 minuets. If they do that all day they must make a fortune!

The salt helps the fish take up oxygen through their gills (I think, not sure).

Salt, in any form, reduces the uptake of nitrites through the gills and into the bloodstream, it is the chloride which does this not the sodium. Greater oxygenation of the water allows the bacteria to grow quicker and reduce the nitrites to nitrates as the conversion is NO2 to NO3. If the fish are being effected you would see erratic beheviour (stress) and high colouration of the gills.
Water change is for total HSM as it can effect chemical balance of the water and slow the bacterial growth (although there is some dispute about this)

Not quite right Dan, one by 50% water change should reduce the level by 50%..a second water change will reduce the 50% level by 50% (nitrite level now around 25% of original reading).

Other factors may be keeping the levels high which I am not sure of...hope you can get it sorted quickly tho

Im am suddenly at a loss without the ability to test nitrites! If the reading really was off the high end of the chart then would this not kill the fish?

The fish are acting fine. I am not feeding them and the nitrite level is staying off the chart.

As close as I can "figure" its like a bacteria bloom. I added the bacteria booster (most likely a sugar). This gave the bacteria a huge energy boost and with the FSB having such a massive area for bacteria perhaps the bacteria are just going nuts with all the nutrients in the tank. The foam on the water must be from bacterial action. When making aerated compost tea foam is the sign that bacteria are working. The only other possibility is some kind of chemical in the water that affects the test.

Assuming that its very active bacteria, I removed most of the gravel from the tank which was loaded with food flake crumbs in an effort to reduce the amount of food for the bacteria. However, that just kicked up a cloud of fine particles that may just be providing more food.

So.. I am still in a bit of a panic..

sleeps hit it on the head with the Cl- ions outcompeting the nitrite at the gills.

the BYAP has the exact ratio of salt to nitrite but since you cant test dose at 1ppt if your fish are tolerant

May be time for a new test kit or some mechanical filtration.
You could make a inline charcoal filter that would take a bunch of the gunk out of the water but should not effect your bacteria population. That is as long as you dont strip all the nutrients out of the water and starve them.

Get a piece of 2" pvc about 12" long cut off a piece about 3-4" long.
Attach a slip by thread reducer on one end of the short and long sections. Thread in a hose barb section that is the correct diameter for the hose you are using on both reducers.

Attach a 2" union on the other end of the short pipe and long pipe so you can hook them back together.

Get some aquarium filter charcoal and floss, put a small amount in the long end of the pipe down at the reducer to keep the charcoal in. Fill the rest of the long section with filter charcoal. fill the short end with filter floss. Screw it back together and then flush it with water to make sure it runs clean.
Attach it to a pump so the water enters through the short section and discharges back into the system through the long end.

Run it till it clears the water up or till your readings are back in line where you need them then either disconnect and save for some future emergency or empty out and let water flow through the empty tube until needed again.

Just filling it partway with floss and charcoal it works preety good for cleaning up solids too.

I am in the process of cutting up LD polyurethane tubing to build a bead type filter; its the only local source for LDPE. I tried using air soft pellets, but I chickened out and removed it because of all the bad press china is getting over led in their crap and because I can not be sure china products are made from virgin materials. After removing it I flushed it out and there was a :booty: "butt-load" of junk that was washed out by the filter. However, that was also about the time that the nitrite test started staying off the chart and the reason I was thinking it could be a chemical problem. So I soaked some of the beads in water over night and tested the water, but that did not seem to affect the test so I hope I ruled out chemical leeching as the reason for the high test readings.

..So anyway.. I was encouraged by the results of the filter and once I get my filter media cut up I am going to construct a bubble wash bead type filter. Like these but from 3 inch pipe:
http://www.ifsolutions.us/bubblebeads.php


I guess the timing of all this is about right anyway. I will be moving the fish to a larger tank this next week anyway, so I needed to stop feeding them before I moved them. The new tank will be green, but the FSB sand filter will be going with the fish. I have to order pond liner for my grow beds. Seems zinc is toxic to fish, so I have to make changes to my plans because I bought galvanized stock tanks for my grow beds. Now I have to line them :/ Which is yet another delay Then there's washing the 6.5 cubic yards of pea gravel to do yet... Grrrr.. I need more spice and that spice would be Tyme!

Are your tests strip or drip tests?

Drip test. I had just bought a new set of test kits too, so I tried the new test kit. Same readings.

You could paint the interior of the galvanized tanks to make them safe.