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could something kill the nitrifying bacteria and stop the cycle?

If anyone has any ideas, I'm stumped. My system is 6 months old, and had cycled just fine. I added 35 tliapia fingerlings. I lost 6 initially, then they were doing great for 3 or 4 months while I fine tuned PH and temp (PH is now 7.2 and temp ranges from 79-84).

For the last month or so, I've had ammonia spiking really high (using am-quel to try to save the fish) and absolute zero nitrite and nitrate readings. I'm losing a tilapia about every three days now. 

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Good question, I am posting here so I can find this thread later, or ifl

Well, it would seem possible that a sustained ammonia spike could potentially slow or stop nitrifying bacteria...but, I'd imagine your fish would all be dead before your bacteria died off? I don't suppose even the famous tilapia are that hardy...

Did you experience a drop in pH before the ammonia spike (hopefully you were taking pH readings regularly and are able to tell us)...?

PH started pretty high, early on, I took a week or two to get it down from 8.3 down to around 7.0-7.3. Every few days, I have to add PH Down because it keeps creeping up. I've used about a fifth of a bottle of the concentrated phosphoric acid over the last 2 months to keep it below 7.5. I just added a whole house sediment and activated carbon filter to get the chlorine and chloramines out, and it comes out of the tap around 7.6 ph. But even between top-ups, the PH consistently marches upwards...

Interestingly, I can't seem to account for many of the smaller fingerlings that never grew up. I did catch one of the big ones chewing on the remains of a little one. So I'm thinking it's possible I have fish decomposition adding to the ammonia? Or perhaps some of the tiny ones may have been sucked up into the pump intake or swam up the bleed valves into the grow tank intake plumbing. I will go clean out the lines to see if I find anyone in there.  

i would NOT use things like amquel plus (from their web page: SPECIFICATIONS
Patents are pending for the formula and it is not available until the patents are approved.)

i don't think there is anything that is going to remove ammonia, remove nitrites and remove nitrates like this product suggests (well, besides the nitrification process).. most aquarium products are not meant for food fish..

how big is your growbed, and how much are you feeding the fish? (what's your stocking density to gb volume)

is your media ph neutral?  the nitrification process will lower the ph.. until then you're just chasing it, and every time the ph is adjusted, fish will be stressed, and thats not a good thing..

my first system ran for 9 months with the ph around 8 before it dropped, and the only supplement i used was maxicrop with iron..very good results.. the high ph will not really harm the fish or plants, but it does prevent the plants from taking up some micronutrients - which maxicrop will provide as a foliar spray or added directly to your system

 

Roe Sie, before you test the pH of your tap water, are you letting it sit out for a day or two (or aerating it overnight) to off-gas the CO2? If not, then you likely have a false reading of your tap water pH. The CO2 trapped in the water after it's made it's way through all that piping will give it a lower pH value str8 outta the tap than it is in reality. Once the CO2 has a chance to escape, you can then take a confident pH reading. Testing the water straight out of the tap is a bad idea (and a useless pH reading). It could be that this is what is causing you to think your pH is 'rising'. It's no small difference either, 0.8 to 1.5 unit values after off-gassing CO2 is quite significant...

Also, look at the ingredient list on that pH down product. If it's the same one that is sold on this site's store, and you are using a lot of it, that might be an (one more)  additional source of ammonia that you don't need. It also has citric acid in it, which is yet one more crappy choice of ingredients to use in a bio-ponic/aquaponic system due to it's ant-bacterial nature. (Seems weird that an AP site would even sell this particular product to budding aquapons)...Anyways...

Yeah, check around for dead fish, un-eaten food, the neighbors curiously missing kitten etc... and see what the actual pH is of your tap water. I'm with Keith in that it seems rather pointless to battle so much with pH at first. And using aquarium products in a food production system, that you can't research the specs for questionable ingredients,  seems like it might be kind of iffy. But it is your system, and your body/family, so make your own decisions, but it wouldn't seem very advisable...

I'm not sure, but I think I remember reading that carbon filters, really don't take care of the chloromines...regardless of the people selling them claim, but you can check on that yourself as my memory is fuzzy on the topic because I don't have to deal with chlorine/chloromine. Rupert of Oz would probably know if anyone does. 

Thanks so much for the response.

ok, no more amquel. and I won't worry about the ph so much anymore.  I've got a decent amount of growbed - equal volume of growbed to FT (150 gal FT, three 50 gal growbeds). I got some liquid seaweed and applied it, will see what that does.

Haven't weighed the fish food, using store bought fish food til I figure out the best alternative, they're all still quite small, so just pinches of food at a time, an amount they'll eat within 5 minutes, no more.

For now, I doubt it's the chloramines. Los Angeles has not fully converted my area from chlorine to chloramine, so I'm pretty confident the filter has managed to take out the chlorine. could it be the copper in the copper pipes?

Keith Rowan said:

i would NOT use things like amquel plus (from their web page: SPECIFICATIONS
Patents are pending for the formula and it is not available until the patents are approved.)

i don't think there is anything that is going to remove ammonia, remove nitrites and remove nitrates like this product suggests (well, besides the nitrification process).. most aquarium products are not meant for food fish..

how big is your growbed, and how much are you feeding the fish? (what's your stocking density to gb volume)

is your media ph neutral?  the nitrification process will lower the ph.. until then you're just chasing it, and every time the ph is adjusted, fish will be stressed, and thats not a good thing..

my first system ran for 9 months with the ph around 8 before it dropped, and the only supplement i used was maxicrop with iron..very good results.. the high ph will not really harm the fish or plants, but it does prevent the plants from taking up some micronutrients - which maxicrop will provide as a foliar spray or added directly to your system

 

Vlad, thanks for the input.. so much great information from everyone! I'm generally measuring the ph in the tank, and have tried measuring it out of the tap for reference, and got pretty high PH readings. so they're even higher than that? wow. Well, with everyone's feedback, I'm going to let nature take it's course, stopped using amquel and ph down, I've used liquid kelp, and I'll see what happens. I can't do any worse than I'm doing already, having lost so many fish. 

I did take it apart and didn't find anything. thanks again for all your great advice!

roe.

Vlad Jovanovic said:

Roe Sie, before you test the pH of your tap water, are you letting it sit out for a day or two (or aerating it overnight) to off-gas the CO2? If not, then you likely have a false reading of your tap water pH. The CO2 trapped in the water after it's made it's way through all that piping will give it a lower pH value str8 outta the tap than it is in reality. Once the CO2 has a chance to escape, you can then take a confident pH reading. Testing the water straight out of the tap is a bad idea (and a useless pH reading). It could be that this is what is causing you to think your pH is 'rising'. It's no small difference either, 0.8 to 1.5 unit values after off-gassing CO2 is quite significant...

Also, look at the ingredient list on that pH down product. If it's the same one that is sold on this site's store, and you are using a lot of it, that might be an (one more)  additional source of ammonia that you don't need. It also has citric acid in it, which is yet one more crappy choice of ingredients to use in a bio-ponic/aquaponic system due to it's ant-bacterial nature. (Seems weird that an AP site would even sell this particular product to budding aquapons)...Anyways...

Yeah, check around for dead fish, un-eaten food, the neighbors curiously missing kitten etc... and see what the actual pH is of your tap water. I'm with Keith in that it seems rather pointless to battle so much with pH at first. And using aquarium products in a food production system, that you can't research the specs for questionable ingredients,  seems like it might be kind of iffy. But it is your system, and your body/family, so make your own decisions, but it wouldn't seem very advisable...

I'm not sure, but I think I remember reading that carbon filters, really don't take care of the chloromines...regardless of the people selling them claim, but you can check on that yourself as my memory is fuzzy on the topic because I don't have to deal with chlorine/chloromine. Rupert of Oz would probably know if anyone does. 

Roe, some liquid kelp products are quite high in nitrogen (anything in the whole numbers range is probably too much) so be careful.

Wait, did you mean copper pipes in the house? Or, copper pipes in the AP system?

Just put some tap water in a glass and let it sit out for a day or two and see what pH reading you get. But yes, it's generally higher than the 'false' reading you get when measuring right out away straight from the tap.

there's no copper in the aquaponics system, i was just wondering about the house plumbing.

So, I've stopped using amquel and ph down, and ph has risen up to 8.6, and ammonia is up to around .25ppm based on the color chart, and still no sign of nitrates or nitrites. I've checked to see if there is any citric acid in the Ph-down from advance nutrients and they only list phosphoric acid in the ingredients.  

Strange that the biological cycle seems to not be operating after so many months. In any case, I'll continue to let nature take it's course, let the ph work itself out (though the aquaponics book recommends keeping a 6.9 ish Ph, I wonder if that's more for established systems?) rather than try to force it. Found another dead one today.

Here's a thought - could a concrete breeze block be leaching chemicals into the water? I put a couple in to support the edge of my grow bed. I had read they are ok, but now I'm wondering...

When I started my system, before I saw nitrites the first thing I noticed was algae. Any growing in your system in the areas exposed to light?

had an algae bloom early on, which vanished a few days after covering system a bit. Have some algae growing on the sides, less so now than before. since that first algal bloom, though, the water has remained crystal clear.

I don't know what a 'breeze block' is, but I do know that concrete that hasn't been 'protected' (with epoxy paint, wax, acid etc)...will cause your pH to rise if in contact with your water. Concrete has a lot of limestone in it and that will leech and raise pH... 

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