Cant Reduce Nitrates

[ac106]

heya guys

I am having trouble with my nitrates in my tank. To refresh:

Hardware:
90G
Rena Filstar XP3
Magnum HOT canister
about 40lbs live rock
Turbo Twist UV
SG 1.020

I have a Sea Clone 100 but they thing just really sucks. It never worked right and hardly collected anything in the waste contrainer. Then it started leaking so i shut it down and I am looking for a better model

I am also going to add more live rock but the cost is making it a slow process.

I am also thinking about adding another filter. I would like a another XP3 but the cost is holding me back at this point.

Software
4 monos
6 scats
2 green spotted puffers
1 Green Wolf Eel

All of the fish are still small, have plenty of room and appear to be ok (feed greedily no injuries or diesese)


Stats
Ammonia: 0
Nitrites: 0
Nitrates: high its hard to tell exactly because the shades of red start to blend together. It could be as high as 80-100. After a 20% water change it went down but not as much as i hoped

I also have a problem with brown algae which i assume is due to the nitrates.

I understand that this can be caused by overfeeding but I am fairly certain this is not the case. The wolf eel gets one silverside a day, the scats and monos get algae based flake and lettuce and the puffers get krill, blood worms and snails. I def do no flood the tank with food and its always eaten, nothing is left afterwards.

I can cut down on feeding and perform some water changes to get it to 0 but this is just a quick fix. They keep coming back.

I am looking to add some marine fish in the future (swapping out some current fish) and need to have this problem under control

Short of constant water changes, is there anything i can do to control the nitrates?






My question is

 

[nmonks]

Couple of thoughts. Firstly, a 20% water change will reduce nitrates by 20%, assuming your water has no nitrate in it. So if you have 100 mg/l nitrate before the water change, you'll have 80 mg/l afterwards. Obviously, if your water has some amount of nitrate in it, the effect will be rather less. Local tap water here in Southern England often has around 50 mg/l nitrate, so in terms of dilution, you can never reduce the ambient levels of nitrate in the tank to less than 50 mg/l however many water changes you do.

Second thing. Don't worry about it. Salt detoxifies nitrate. Most brackish water fish don't care.

Once you're at a marine SG, you can use live rock to control the nitrate to some degree, but to be honest I've never found denitrification in the aquarium to be effective with big, active fish. There's logic to using it in tanks where you're using nitrate-free water (RO water) to begin with, because then you don't have a big load of nitrate in the "fresh" water you add at each water change. But if your tap water has 50 mg/l nitrate anyway, as it does here, the denitrification effect is trivial.

Cheers, Neale

 

[ac106]

Heya Neale

My tap water, since moning in July has 0 nitrates.

usually I wouldn't worry but there are a couple of things that have me concerned:

First, i have a lot of brown algae. Is there any other way to control this? I know a trick is to encourage green algae but I have never been able to do this

Second: My Green Wolf Eel is black all the time. At first, i thought he was blending into the black sand. I then switched to light colored sand but no change. I was thinking it was the nitrates stressing him out.

Third i was thinking of adding some other marine fish like a Dog Faced puffer. They are more sensitive to nitrates arent they?

How much live rock would i need to make a dent? Also would a better skimmer help?

 

[nmonks]

If you have 0 mg/l nitrates in your tap water, then do a 100% change and measure the increase in nitrate across a week. You're safe doing a 100% change because the salt mix will buffer to the right pH/TDS right away, and your fish can adapt to changes anyway. So, by doing this, you'll establish the baseline, and you can see how quickly nitrate goes up. If you can see it going up by 20 mg/l per day, then it's almost certainly fish/feeding.

You get brown algae (by which I assume you mean diatoms rather than kelp!) when there isn't enough light, as far as I can tell. Green algae needs "proper" lighting, while diatoms don't seem to care. Regardless, it isn't an issue, and certainly won't be *adding* to the nitrate. If anything, it's a nitrate sink, converting dissolved nitrate into algae that can be scraped and siphoned away.

Arothron spp. are nitrate tolerant, but in general, you get better results keeping marine fish across the board when nitrates are low. While Arothron spp. will be the last fish to complain, you shouldn't really be imposing on this.

A skimmer can help, especially if the nitrate source is particles/liquids the fish can't eat (for example, the "juices" from meaty foods).

Can't comment on the live rock issue; not enough of an expert.

Cheers, Neale