NITRATE PROBLEM

[Drstrangelove]

Hey Guys, I have very high nitrates and I don't get it. Tank is a 125 I have 2 big canisters, a H.O.B. with purigen pack in it ,a powerhead and a sponge filter *. I have recently added 3 bunches of pothos and a soda bottle with ceramic rings to the powerhead and more rings in the H.O.B. .Rings were just added ,pothos added a month ago .I do 40%ish w/c every 4 days or so .All other parameters are great on My A.P.I test kit but nitrates are always over 40% .I even tried back to back water changes 2 days in a row for a total of about 75%....No difference! Stock is 10 Festae grow outs 3.5 to 5" and a school 7 of clown loaches( 3"ers)....Maybe a bit overstocked but I thought I could counter that with lots of water changes and what I THINK is plenty of filtration?.Tank has been running since Dec. but some of the filters have been running for close to 10 years. I use prime and have even tried double dosing . I am gonna take a sample to L.F.S. just to see if My test kit is bad....Also gonna add more media to My cans.....I am truely *puzzled. Any advice?

I can't really follow your numbers.

1a) 40% WC every 4 days
2a) nitrates always over 40

then

1b) 40% WC 2 straight days
2b) nitrates still over 40

To have a steady steady at 40 ppm of nitrate in a 125 gallon with 17 4.5" fish, you need to be feeding around 15% of body weight per day (50% protein). To make up that much nitrate in a couple days (~65% of the water removed in the 2 WC, took out about 26 ppm of nitrate), you have to be feeding your 17 fish about 30% or their body weight per day. How much are you feeding?

Also, what color is your purigen? Are you cleaning it?

 

[dogofwar]

How often do you clean th e mechanical media in your canisters? The same crap that you siphon from your gravel is in them...

Matt

 

[DDK]

^ That sounds like a good place to start if your nitrates aren't clearing up after constant water changes. I would do a once over on all the mechanical in all the filters. Just rinse the bio media and then leave it in the tank or bucket and you won't have a cycle. Important thing is to keep the bio media wet at all times.

 

[dogofwar]

It astounds me that people gravel vac frequently and only clean their canister filters every 6 months or when they stop flowing.

I try to clean mechanical filtration weekly.

Matt

^ That sounds like a good place to start if your nitrates aren't clearing up after constant water changes. I would do a once over on all the mechanical in all the filters. Just rinse the bio media and then leave it in the tank or bucket and you won't have a cycle. Important thing is to keep the bio media wet at all times.

 

[duanes]

I agree with Matt, one of the reasons I won't use canisters.
When I had them, canisters were very unuser friendly (as far as ease of cleaning). The tendency was to let them run long periods without cleaning, and become nitrate factories. Unless things have changed as far as ease of cleaning goes, I suspect that is the high nitrate causing culprit.
And not only the mechanical media, I found in mine, lots of gunk would end up clogging the biomedia, so in order to bring nitrate down, I would need to rinse the krapp from the biomedia with old water change water before returning it to the filter.
Because beneficial bacteria is aerobic, or at least facultatively aerobic, gunk defeats the purpose.

 

[1eyedbicher]

Thanks Guys, My canisters are cleaned often ,I rotate schedule so 1 every 3 weeks or so, I dont let sludge build in them ...I may leave one pad gunky as I want to leave SOME action in there. but yeah I actually clean the inside of the can.In the past (been doin this over 20 years so lots of mistakes)I had left them too long and have seen how bad they can get soooo I clean them pretty good. I am sure My purigen could use a re-charge(doin it this weekend).all the new rings I added in the last weeks should start making a difference soon(yes?) and My pothos are taking off pretty good.I DO believe I am probably overfeeding ,I wanted to pump them up as babies and probably should roll it back about now,but when they are not feed often the chaos level rises greatly.I am setting up 2 more tanks to lessen the load on this tank and lower the violence ...I have been waitin to see a pair before splitting them up but they are getting too big and mean to have them all together much longer. Thanks for all the help M.F.K.