water change.. How long to wait.

Hey Guys and Gals,

I have a 120 gallon in wall tank and am having issues with Nitrates.. well, some would say not a problem as they are only 20 but they are not zero. Anyway I did a about a 13 gallon water change three days in a row. but the nitrates have not moved. I am also going to try changing out my filter socks every other day for a couple weeks to see if that helps.. Anyway my question is with doing the 13 gallon change three days in a row. Did I do too much? How long should I wait before doing additional water changes? Any help would be nice.. My tank is doing really well just would like to see the Nitrates down a tad. Thanks of reading this!!

 

Nah, changing the water is one of the best things you can do for your tank. Just make sure your not shocking your animals by salinity, tempature, PH, etc. If your using an RO type water it should be lowering your nitrates in there with every change. Has something recently died in there? I find that my hermits will die and make my water fluctuate a little sometimes. Also if your nitrates are staying at that level it could indicate that you have a higher bio-load, or your over feeding. A means of nutrient export (macro algae of some sort for example) would help you get those figures down to where you want them.

-Gavin

 

That covered it nicely. You didn't do any harm, I agree there whole-heartedly. I would seriously consider either a denitrator combined with a phosphate reactor or do the refugium thing. You can do a combination of the three if you desire....it just depends on what your tank finds successful. Your aquarium is young yet, so you can procede at your own pace. What is your bioload?

 

I would check your new water for nitrates, but at 13 gallons at a time the nitrates are only going to decrease by 10 percent or less. How many fish do you have and what are you feeding them? Has the tank been running for a while and the nitrates are just now a problem? Also why are you running filter socks, I always found them to be a nitrate source.

 

Hi Remick J
1stly I doubt 3 consective days of 10% water changes are going to be a problem in that sized tank

2ndly - with nitrates at 20 ppm the best you can achieve with a 10% water change is a reduction to 18ppm - then by the time you do another 10% water change the following day your nitrates may have crept back up to 20ppm and yes after the change you are back down to 18

in fact the difference between 18ppm and 20ppm would probably not be noticeable on the test kit you use - so to your eyes it would seem your nitrates are as they where before the 3 days ( and they probably are in reality)

20ppm is not high and naturally you want to achieve 0 - as a pre emptive measure against nuisance algaes I assume

simple measures include

do the sock changing you suggest, clean any mechanical filtration device or media on a weekly basis when you do water changes

make sure you have no dead spots in the tank where waste can decay

periodically blast the rocks to remove detrius and syphon

dont overfeed, uneaten food is one cause but so is excessive fish waste

increase skimming capacity, remove those protiens before they break down


more complex measures include

checking your filtration set up, are you biased towards oxygen requiring bacteria species and lack adequate real estate for the anaerobic species that convert Nitrate to nitrogen gas.

increasing areas for anaerobic bacteria either in the form of live rock, live rock rubble or a denitrator coil

using a chemical filter medium designed to remove Nitrates


But if you dont have an algae issue - 20ppm is not a problem IME

Steve

 

Thanks for all the input. I'm going to try to give some additional info to cover all posts. Sorry I should have given this up front with our form.

- I have a sump with a fuge that does hace macro algae in it to try to keep nitrates down.

- In the tank I have the following: 4 inch sailfin tang, six line wrasse, two false perc clowns, orange spot goby, algae blenny, snails, hermits (not sure of the number) Maxima clam, 3 cleaner shrimp, 1-2 Emerald crabs.

- I also have a bunch of corals: some I forget the name of (that will be another post) others include Xenia, Colt Coral, Orange Sponge, Umbrella leather, Finger leather, green finger leather, frog spawn, Button pylops, star pylops, gonipora.

Really I have more corals then anything. The Nitrates have been high my guess is that they may have gotten there because when I did my water changes I was only doing about 13 gallons every few weeks and I'm not sure that it was enough. I'm not feeding often at all.. I make sure their is Romaine in for the Sailfin. then I feed pellets OR formula B frozen food daily. When I feed Frozen food I thaw it out in a container and rince it in a net to get any really small food items that would just end up settling in the rocks out. I will look for dead spots but I don't think I do I have a Mag 1200 as a return for the sump then in the display tank I have two Eco Tech Marine MP40w's that move some serious water.. Only thing I can think is that I've never vacumed the sand bed. I know there are different opinions here.. Maybe I should try that?? Anyway sorry for the long reply just wanted to give you all more information.. Let me know if this information gives any more ideas and Thanks for the responces so far.. K+ to all.

 

Sounds like you are doing every thing correctly. How does the refugium grow, fast, slow barley at all?

Have you ever tested your make-up water? How old is the test kit?

 

I put about two softball size balls of macro algae in the tank when I started it in October of last year. Since then they both have grown enough that the fuge is full (it's a 15-20 gallon sump with a portion of it being the fuge. My test kit was bought maybe in August of last year.

 

Sounds good to me. Test your make-up water and continue on the same course, I suspect you will get the results you are after soon enough. Cut the water changes back to weekly. I prefer a 10-15% every other week.

 

The zero nitrate is a debatable issue. I am sure from time to time you could catch your tank at zero, maybe after a substantial water change, and if you are one that does weekly changes (of which I am not a fan) you may keep reading zero or next to zero. However, that does not mean there are no nitrates.
Nitrates are a result of a healthy aquarium. It shows the natural process of waste being broken down. One contention I have about readings from test kits is, how accurate is that particular test kit. This in and of itself is a debatable subject for another time. From my own experience and seeing what is used in many lfs around my area I use the American Pharmaceuticals brand. Their nitrate shows nitrates when others don't. I am not promoting, just telling you my experience. Many corals (especially soft) actually use nitrates. A low level is beneficial to them. In my estimation many reef keepers become obsessed with the whole zero nitrate idea to the extent they are constantly doing water changes and disrupting the water chemistry in their tanks. Keeping nitrates low is optimal to the overall health of your tank but obsessing over it is needless worry.
Far to many aqurists are more concerned with nitrates than overall water quality i.e. Calcium, Magnesium, Alkalinity, Iodine,SG and PH. Keeping these stable and not allowing big fluctuations is far more important for the health of the inhabitants of your tank. Too many times I have read on this and other forums where people state they don't even have test kits for some of the things I mentioned and worse yet are adding supplements blindly! And no, water changes don't necessarily put back all these things in the correct proportions and so that's all you need. Mag, calc and others can be used up quite fast in a biologically growing tank. The sea is very stable actually and the closer you can get to mimicking it's level and stability the better off your system will be.
Also, nitrate can enter the system from a variety of sources, as I think you are aware. From reading your posts you seem to on top of all your maintenance and feeding protocol. I don't recall a mention of a protein skimmer and although a skimmer is not an end all it certainly goes a long way in purifying the water. You may have what I call "stubborn tank" syndrome. I had the exact same thing and just accepted 20 ppm as my "norm".
One day I went to one of my trusted LFS (quite a drive) and talked with a buddy their and as a last resort kind of thing he said "why not try some Halimeda". I had to put it in the display but was not opposed to it and I enjoy the green in the tank. To my knowledge no fish will bother with it and they haven't. Well, after it got well established (about 2-3 weeks) the nitrate is reading zero and it has been about a year.
Now, it does use calcium to grow so you have to stay on top of that. It is hard to find locally but you may want to try it in the fuge.