HELP Please! Nitrates still high . . .

[horsewhisperer]

OK. I have tried EVERYTHING I can think of! This is my tank . . .
29 ga.
Flourescent light that came with the tank
Whisper hang on Filter w/ nitrate sponge and carbon
CPR backpak protien skimmer, with live rock (took out bio media)
Roughly 15 lbs. live rock
2" live sand bed

4 seahorses
2 fan worms
bunch of snails and crabs
peppermint shrimp

Salinity avg's 1.025
Temp avg's 75-76
PH tends to run low, 8.0, we raise it with buffer about every other week.
Nitrates avg. 20 ppg.
Nitrites not discernable
Ammonia no traces

Feed 1 frozen mysis cube twice a day, using a syringe for target feeding, rinsing in purified water first. I DO put my hand in the water to do this. I put the food in a shell I use for a feeding station and on the rocks in the immediate area of the shell.

We have been doing 25% water change twice a month lately. Before we started using the skimmer our nitrates were even higher and we were doing water changes every week. We use both salt mix with purified AND changes with Live Water. (Yes, we have tested the live water before it goes into our tank, and there are no nitrates!)

There are two different types of plants (algaes) growing in the tank.

Any suggestions? What are your tanks parameters for Nitrates? Am I overfeeding? The horses are hungry when I feed them, and all eat all the food right away. IF anything is ever left for any amount of time, the crabs come and get it.

I read about all these tanks that read NO nitrates I don't know what we are doing wrong! Thank you!!!

[hawkfish21]

If you overfeed like I do, change 20% of the water every week. My nitrates are always 0.

[ReefNutPA]

I'm wondering what the nitrate level is in your reef tanks and how those tanks are set up. Reason I ask is my seahorse tank is set up like a reef (live rock, 4" DSB, skimmer) and nitrates are 0 just as in my reefs.

The only obvious thing I see is a 2" sandbed really isn't deep enough for efficient denitrification. It should really be closer to a 4" depth. Additionally, having 1 lb or more live rock per gallon helps tremendously with water quality (including nitrate reduction).

If your crabs are like those in my reefs, they don't eat the entire piece of food they grab. They eat bits of it but some of it floats away or lays on the sandbed. This, depending on the amount your seahorses leave uneaten, would definitely cause a nitrate increase as the bits of mysis decay.

Except for the depth of your sandbed and amount of live rock, your tank sounds no different than the "seahorse reefs" most others have, including myself.

How often do you change the Whisper filter bag? I rinse mine off at least once a week, sometimes twice, and replace them monthly. If you don't keep the filter pads clean, uneaten food particles just hang on the filter bag waiting for you to replace it which is the same as the food laying in the tank decaying/raising nitrates.

At this point, I'd keep the filter pads clean, siphon out uneaten food (the crabs won't starve), do water changes weekly until the nitrate level comes down.

As far as the sandbed, you can increase the depth... but it's advisable to only add about 1/4" of sand every week or so until it's the depth you desire. Adding more than that will kill off some of the nitrifying bacteria. By adding 1/4" at a time every week or so you give the bacteria time to migrate/colonize up into the new sand.

I'm sure others may have further/different suggestions. I thought I'd offer my opinion though until others respond. Hope everything works out for you.

Tom

[MinuteJohn]

I fought the nitrate battle too. Here's what worked for me. I added a HOB fuge with Chaeto and some caulerpa, halmeida and red kelp to the display. That and a 10% WC once a week. I have to harvest the chaeto and caulerpa once a week. I still overfeed BTW.

What kind of Macro is in the tank? You should be getting great growth on your macro. If it is a slow growing or high light macro, it won't do much to reduce nitrates though.

I dose a little iron to keep the plants growing healthy too.

With 4 horses in a 29 you are going to need some serious nutrient export. I recommend some sort of fuge with chaeto. You could also go with a remote deep sand bed, or DSB in a bucket.

Good luck

[DanU]

Unlike corals, I find seahorses aren't particularly sensistive to nitrates. I wouldn't get shook up at at your current level. Having said that, there are some good suggestions above to help keep them in check.

Dan