Water changes and Nitrates

Sammydog

Sammydog

Reefing newb
We currently have high Nitrates in our tank (about 140ppm). I had been changing the water, about a quater of the tank, about three times in the last two weeks but it hasn't really come down.

I changed the water this morning (new water tested as zero nitrates) and once added to the tank the tank came down to 40ppm. I am going to test again tonight.

My question is, how often can I change the water? Can you change it too often. If it is ok I want to change each day (or two) until the source of the high nitrates is found.

All other parameters in the water are fine and I have been led to beleive that the high nitrates were to be expected as we moved the tank from another house. The reason I am a little worried at the moment is that there was small dead shrimp (about five) on the sand this morning. There was a bristleworm out at a time I have never seen them as well.
 
Do you have an RO water filter? If not, I would consider getting one right away.

As far as how often you can change water......... I don't think it's bad to change about 10% every couple days if you are trying to slowly reduce nitrates. I wouldn't change more than 20% on one day. 10% every 2 or 3 days for a couple weeks straight would be my approach. It should reduce the nitrates back down to acceptable levels slowly. This would be less stressful on the fish and corals IMO.

WHY do you have nitrates? Is it because you had to disturb the tank in the move or is there an underlying problem that needs to be dealt with? What type of filtration system is on the tank? Do you have live rock? How much? Canister filter? Sump? Refugium? Macro algae? Wet/Dry filter?
 
To move the tank we essentially had to remove all the live rock drain the tank into containers and put it on a trailer. It was then reassembled at our place. I've been told that this type of move may be the cause but we are still looking at other potential causes.

I don't know the weight of the live rock but it takes up a fair portion of the tank.

I'm not sure what you call the filter, it's on top of the tank, water is pumped up to it and the water trickles through a filter medium and some crushed live rock

would a protein skimmer help? The local fish shops have all advised not to bother for a 90litre tank.
 
Yes, a protein skimmer would absolutely help. I won't have a salt water tank without one.

What about the RO filter? Do you have a Reverse Osmosis water filter to cleanse and purify your fresh water before you add the salt crystals to it?
 
I don't use RO water but testing the levels of the new water the nitrates test as zero before it goes into the tank

I've spoken to a few aquariums around here and all of them said that we wouldn't need to get an RO unit. Advice on here definitely seems to be contrary to that advise. Might have to look into a unit (funds permitting).

Even with the new water showing no nitrates would this be likely to be our source?
 
No, if the water going in shows zero nitrates, that's not causing the problem.

What kind of substrate do you have? Sand or crushed coral?
Do you use flake or pellet foods? Or frozen?
Do you have a tendency to overfeed your tank? How often and how much do you feed?

Your filtration system could be causing the high nitrates. Filters like that have a tendency to do that. A protein skimmer is far superior to that type of filter and won't lead to nitrate problems.

Keep doing water changes -- 140 can be fatal to your inverts and corals. Your nitrates should not be over 20 if you are trying to keep inverts. You can safely do 20% water changes every day.

Once you get your nitrates down, you will have to keep them down... It does sound like this is a by-product of the move. That tends to happen when rock and substrate gets moved around -- all the crap that was trapped inside and underneath it is all of a sudden released into the tank. If that's the case, you need to keep doing water changes to get them down to an acceptable level.

If water changes don't seem to be helping, get your water tested again. You may have used a bad test kit (it happens a lot) and the reading may have been wrong.
 
No, if the water going in shows zero nitrates, that's not causing the problem.

What kind of substrate do you have? Sand or crushed coral?
Do you use flake or pellet foods? Or frozen?
Do you have a tendency to overfeed your tank? How often and how much do you feed?

Your filtration system could be causing the high nitrates. Filters like that have a tendency to do that. A protein skimmer is far superior to that type of filter and won't lead to nitrate problems.

Keep doing water changes -- 140 can be fatal to your inverts and corals. Your nitrates should not be over 20 if you are trying to keep inverts. You can safely do 20% water changes every day.

Once you get your nitrates down, you will have to keep them down... It does sound like this is a by-product of the move. That tends to happen when rock and substrate gets moved around -- all the crap that was trapped inside and underneath it is all of a sudden released into the tank. If that's the case, you need to keep doing water changes to get them down to an acceptable level.

If water changes don't seem to be helping, get your water tested again. You may have used a bad test kit (it happens a lot) and the reading may have been wrong.
 
Water going in definitely shows zero nitrates. I've had the water tested by the LFS regularly and my readings agree with theirs so I think the kit is ok.

I will continue with daily changes to get the levels down and look at a protein skimmer as well.

We have a crushed coral substrate. Probably about half an inch deep.

Food wise (4 black clowns and a mandarin) we give a small pinch of pellets once on mon/tues/thurs/fri/sun. Wed and sat we put in a half cube of shrimp (rinsed of the brine it is frozen in).

Thanks for all the advise so far too, it's been great at helping me get a handle on this.
 
Eliminate the pellets-- they have lots of nitrates in them. Use frozen foods instead. Get rid of the crushed coral-- it's a poop trap, which means the trapped debris will rot and eventually cause high nitrates. Use aragonite sand instead.
 
If you wish to keep the crushed coral I would reccomend siphoning detritus out by disturbing the crushed coral during water changes. You can keep it if you wish but it bwill take extra work that is not nessicary or reccomended for aragonite sand.

I will definitely jump onboard with getting a skimmer. I run one on all my tanks, even my 10 gallon which I believe is 37 liters? You will be amazed at the amount of crap you see in the collection cup.

Best of luck to you with maintaining order in your tank. Sounds like things are headed in the right direction.
 
I already vacuum the crushed coral when I do water changes but I am going to look into the aragonite sand tomorrow when I go to get more salt. Will look into a protein skimmer as well.

For now I am going to do 20 litre water changes each day (90 litre tank) to try and keep it under control while I find the source of the nitrate issue. We have cut back the food so hopefully it does just stem from upsetting the tank in the move and we can get things back to normal in the short term.
 
Two possibilities: if the rock dried out during the move living stuff on it died and caused a nitrates spike when you put in back in water.

During the move the water and rock got too cold and stuff died?

Dead stuff and fish poop (detritus) generally cause nitrates.
 
Rocks were kept submerged during the move and nothing died that we are aware of.

Water would have been unlikely to have chilled much the day we moved as well.

I'm starting to guess that the move stired stuff up and I've also probably been slightly over feeding, so I have cut that back.
 
This is where a skimmer would help a lot. It will remove the dissolved organics from the water before your aerobic bacteria have a chance to begin breaking it down. The natural by product of aerobic bacteria breaking down organics is nitrates. If you can get the organics out of the water before they break it down you'll have less nitrates.
 
I'll be looking at skimmers today. Despite being told by the LFS we don't need one because of the size of our tank, I think now I would rather have one.
 
Most LFS in the USA have a bad reputation because they do exactly as your has done. They give you BAD advice and take your money selling you items you don't need.

If I were you, I wouldn't return to that LFS ever again for advice or equipment. You might purchase corals and frozen foods from them because it's convenient. But as far as getting advice or equipment from them - I say SCREW 'EM!! They haven't done you any favors so far and they won't likely do you any favors in the near future.
 

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