How often should I do water changes?

[Dundermifflin]

With a 120 gallon FOWLR how often should I change the water?

How much each time?

How often should I vacuum gravel?

*The fish in there will be snowflake eel, triggers, tangs, porcupine and dog face puffer

[tomreefer]

Well you can do a 10% water change weekly or a 25% change monthly. I would suggest 12 gallons a week. What are your parameters? Nitrates etc high? Gravel for sure will collect detrius so you should concentrate siphoning every time u do water change.

[JammyBirch]

I have a 25g so some may not agree with me but here goes. I do a 20% change twice a month! I found that I can replenish trace elements and reduce nitrates enough to not have them add up. You have to reduce nitrates enough so your baseline, what nitrate is still in the water after the water change, is reduced enough that your total nitrate concentration will not grow higher and higher at the end of the water life.

If I were you I'd be measuring you parameters weekly to figure this out, I'd also start doing 10-15g a week and see if this works. I think every tank is different you have to figure it out with the data.

I'm a huge fan of water changes, which is easy to say when I only do 5-7g every other week, but the tank is so clean and easy to deal with its worth it.

Get some brute tubs, check out some of the BRS videos on YouTube they go into a lot of detail for large tanks and get a Python for water removal. I love that thing it can remove 5g of water in under a minute and I never spill a drop.

I hope the nitrate thing is not confusing it's hard for me to explain...sorry.

[JammyBirch]

I don't vac the gravel, it's live sand for me, and will be live gravel for you too. I have cerith snails that tool around in it eating detritus keeping it clean, churned and leave the good bacterial in it.

[tomreefer]

I agree with the above. Your first water changes I would recommend higher depending on your nitrates. The nitrates are a major issue in most tanks especially when it just finished cycling. My tank first was showing 40ppm and I think the tank was actually a lot worse since their was a major outbreak of algae. If you have a lot of algae take a note that what your test kit measures maybe actually more since algae feeds on nitrates.

[whosurcaddie]

I have the same size tank as you I do 25 gallons every two weeks. But I have a reef tank. Honestly man with a FOWLR I would set up a bio pellet reactor and be done with it. By setting up the reactor you could do a water change probably twice a year and be fine. And that's only to replenish trace elements. In a FOWLR your not worried about corals only healthy fish. The biopelets will drop your nitrates to zero and keep them there. This is of course dependent on a good skimmer but if I was running a FOWLR its exactly what I would do and I wouldn't think twice about it.

[mdelp]

So my tank has been up and running for about 7 weeks and I have yet to make a water change. I have no coral, one anemone, several invertebrates and community fish. I keep checking my Nitrate levels and it never looks like they are above 10 ppm. I'm not sure why this is, I don't have any chetomorpha or anything like that to eat Nitrates. I have a good skimmer. I keep waiting for the Nitrate level to get higher to do a water change but it hasn't happened yet. I do have to add about 48 ounces of water every day or two to keep up with the evaporation which seems like a lot to me but I have no reference (tank is covered). 54 gallon tank. Should I do a water change just because??

[tmz]

Opinion about the amount and frequency of water changes needed vary. Water changes add major, minor and trace elements . How much a given tank needs depends on lthe organisms and the consumption of these elements as well as any supplements being added. For example a tank with stony corals and or clams will use more calcium and alkianity than a FOWLR tank. They also remove some nutrients but that is a lessor function as nutrient levels are primarily a result of balance or imbalance between inputs via foods and overall filtering capability.

FWIW, I do 1% daily water changes to promote constancy . Iaslo supplement calcium and alkainity via limewater for the mixed reef system.

[Timfish]

Whatever combination that adds up to 25% - 30%. There are things going on that are beyond our ability to test. I always hear people touting if you do this or that you don't need to do water changes but they don't seem to stay around very long. With multiple systems over 2 decades and no regular supplements I'm convinced of the efficacy of small weekly water changes.

http://youtu.be/Vs_etaHSOfQ

[jstephens24]

interesting b/c i have a 75 gal FOWLR and have gravel as well. I am still waiting for cycle to end but I like to know as much as I can about how other people's setups run that are similar.I was planning to do a WC every other week of 20 gal but if I could do that maybe once a month that would be better.

[FraggledRock]

Originally Posted by jstephens24

interesting b/c i have a 75 gal FOWLR and have gravel as well. I am still waiting for cycle to end but I like to know as much as I can about how other people's setups run that are similar.I was planning to do a WC every other week of 20 gal but if I could do that maybe once a month that would be better.

Once a month is kind fo too long.

your elements will drop so significantly that when you do a WC you will be raising all the parameters up so fast it may shock your corals.

ex: in one month your magnesium could drop to lets say 1000 ppm.

when you do a water change it can go up to 1300-1400pmm

this will throw off your calcium and Alkalinity. big raise.

which will throw off your PH. then you will start wondering why and start dosing other things that will fluctuats other parameters till you have a tornado of fluctuations and the whole tank becomes unstable.

Which will make your SPS (if you ever get into that) very unhappy and probably die.

weekly is good. your parameters will drop at most 10% depending on what you have growing.

if you don't have any corals, you may not even see any loss of calcium or magnesium at all for a long time.

[jstephens24]

If/when I do corals I would do WC more often but i am doing a FOWLR. So i dont think the calcium/alkalinty would matter

[Tsancho82]

mdelp, you have an anemone in a 7 week old tank...? How long has it been in there and how is it still alive?

7 weeks isn't that long, you could still be going through your cycle, that's maybe why your nitrates haven't spiked yet. I would get that anemone out of there and put into a matured system because it's not going to make it in such a young establishment. It is likely going to die due to lack of nourishment created by the ecosystem doing its thing over time, and if that happens it could tank your tank.

Do yourself a favor and research before just buying something because you like it. It'll save you tons of money and heartbreak in the long run and make this hobby much more enjoyable.

[cloak]

Originally Posted by Dundermifflin

With a 120 gallon FOWLR how often should I change the water?

How much each time?

How often should I vacuum gravel?

*The fish in there will be snowflake eel, triggers, tangs, porcupine and dog face puffer

For a FOWLR tank and those inhabitants I would probably vacuum the gravel or stir it up at least once a month, and change out maybe 15 gallons every two weeks. Basically just treat the tank the same way you would a freshwater tank full of ciclids or something. Don't overthink it.. Once you develop a routine & stick with it there's no reason why your tank couldn't last for years on end without any problems. GL.

Don't forget to QT btw.

[Mishri]

Yeah, like cloak and showsurcaddie said. FOWLR don't have many requirements, you do have to replenish trace elements, twice a year would be a minimum in my mind. Good filtration is key. I'd still feel better with monthly but you can get by with less.