Keeping up with nitrates

[Scoot]

I've been doing 30% PWC on my FOWLR 75g every 4 or 5 days, for the last 2 weeks, and I can't seem to keep nitrates down - every morning they've crept back up to 20ppm.

I'm using an emperor HOB filter, I have 5 small fish (the biggest is a 4" anthias), 14 hermits, an arrow crab and a cleaner shrimp.

I have a batch of chaetomorpha on the way, I understand this might help some, I'm also building a sump/refugium to keep it in. I think I'll find a hang-on in-tank refugium for the chaeto until my sump is ready.

I've been vacuuming with each PWC, keeping feeding to a minimum, and all other param's are great (0 ammonia, 0 nitrite, 8.2 pH, 1.022 SG).

Meanwhile, any products or tips to cut down on nitrates, without using something that will remove ammonia and compete with the nitro bacterium?

 

[tecwzrd]

I assume you have tested your source water for no3. If it’s not 0 then you will always have no3 since you are never removing it.

If your source water is 0 no3 then that amount of water changes over the last 2 weeks should get it down to <10 ppm depending on what the reading was before you started.

Do you have more then one test kit or have you taken it to the lfs to verify the 20 ppm is correct? Old AP tests IME will display a higher reading then others.

Have you been cleaning your filter of trapped waste every time you do your PWC? I use a sponge on the intake to my filter to keep waste from being trapped and rinse the sponge out every other day to keep no3 down. The other advantage to using a sponge on the intake is that fish and the clean up crew can get to anything trapped on it. (assuming you have rock close by)

If you have aragonite sand you shouldn’t have to vacuum each time. I only vacuum my sand about once every 3 months and then only the top 1” layer. How deep is your substrate? The clean up crew should keep it clean for you. I noticed you didn’t mention any sand stirring snails.

 

[dskidmore]

How old is this tank?

Could something on the live rock be dying and decaying?

There are pretty much only 3 sources of nitrates: food, source water, and dying critters.

 

[Scoot]

Tank is 8-9 weeks old now.

Tap water is free of nitrite and nitrate (it has ammonia though, which seems to be knocked out by Prime).

Yes, rinsing filter well, in salt water.

There's a grill-type thing on the filter intake - fish can be right next to it and it doesn't seem to pull them to it. My arrow crab has been right on it, he has no problems getting off. A sponge might be easier to clean though.

Yes, I have two separate test kits both read the same - I'll probably take some with me next time I go to the LFS to verify.

I have LS, about 2.5 - 3". I havent' been doing a "deep" vacuum each time, I've been told it can remove too many beneficial things.

No sand-stirring snails.

There is a lot of particulate matter in the water, whenever its disturbed (adding water, moving rocks, etc). Should I be vacuuming over the LR?

 

[tecwzrd]

Your tank is new and hasn’t had time to fully stabilize yet. The nh3 in the tap water is kind of scary and I hope you are not drinking it. Seachem Prime detoxifies the nh3 but doesn’t remove it. That means its still an nh3 source which converts to no3 which could be a big reason it might give you a lower no3 reading hours after the PWC but then go back up to 20 ppm quickly.

I’d really consider getting a ro/di unit before buying/adding anything else to this tank.

The grill-type of pre-filter on your intake is fine for keeping fish/inverts from being sucked up in the filter but still will suck up any floating food which gets trapped in the filter to decay and eventually convert to no3.

Using a sponge that you can easily remove every day or so and rinse will help particles from getting trapped in the filter. Also larger pieces of food can be picked off by fish/mobile inverts.

Particulate matter in the water when disturbed is fairly normal and should clear up within a couple of hours. You could run your siphon just over the top of the lr to collect any loose particles but it’s probably not necessary.

If you get a mix of about 10-20 Nassarius & Cerith snails to start off with you shouldn’t have to mess with the sand at all.

 

[Scoot]

I understood from the municipal water report that I read (and posted somewhere) that the ammonia reading could be coming from chloromines added to the water, that my test kit (and alert badge) are picking those up.

I'll find some filter sponges for the powerheads and filter.

I've added another powerhead (for circulation), it seems like a lot of stuff is settling on the LR, when I move them at all, stuff really comes off them. I dusted them with a baster today, hoping the filter will pick up some of it.

I'm researching RO/DI filters. There are some on eBay for $100 with shipping (6 stage), 100 to 125gpd units.

 

[dskidmore]

RO: The slower unit is usually the better one. The faster unit usually doesn't purify the water as well. Are you going for a tank/tap, float valve, or just connect and disconnect as needed?

 

[Scoot]

Connect/disconnect as needed. Something that won't need plumbed, that I can set on/near my utility sink.

On the phone with water company.

The boss of the chemistry dept. himself owns a SW tank (with a single lion fish who has a voracious appetite for any other creatures).

He said to use a "sulfite" based condition to avoid separating the ammonia into free ammonia, that the thio-sulfate would result in free ammonia added to the tank.

He also said the total nitrogen in the water (which includes chloramines and ammonia) is less than 3/10th's ppm, and free ammonia should be less than 1/10th ppm (unless separated by a thio-sulfate-based conditioner).

Does that make any sense?