Water Changes....how often should I do them?

[C_R_V2000]

Hello nano reef community! I have a 24 gallon cube reef tank and I was wondering what is the recommended water change schedule for a tank this size? Would 10% a week be better or 20% every other week?

Some relevant info:

I have some small sps frags that use up calcium/alk but not at an insane rate

Nutrients stay pretty stable at pretty much zero for both nitrates and phosphates

 

I do have a small GHA outbreak atm but I have a more than capable cleanup crew that keeps it relatively in check. 

Feeding schedule is 1 time a day, twice every other day. 

 

More about my livestock on my journal page, the tank has been up for about 8 months, I'm just wondering what the optimum water change schedule would be

[Clown79]

Phos and nitrate shouldn't be 0, thats not beneficial. The tank needs both.

 

Waterchanges should be based on need. Each tanks needs are different.

 

I started with 10% every week but eventually my tanks did better with 10% every 2 weeks. My tanks ran very clean and weekly waterchanges led to no nutrients so I changed it. 

[Afropenguin]

On a new tank, id probably do them more frequently (10% once a week) and as the tank gets older you can adjust based on how things look. For my tank which has been up for 2 years, I do a water change once every 3ish months to get the salinity back to the same level.

[travoose]

I started off doing them weekly, noticed no growth in my tank.  Switched to every other or even third week, things have took off.  Tanks need to run a little “dirty”.

[MainelyReefer]

Weekly, it’s dependent on your husbandry. If you don’t feed a lot every other week might be good due to nutrient levels.  I feed a pinch of flakes, pinch of pellets and a cube of frozen daily.  And more on the weekends so the weekly WC is highly beneficial.  That being said life wins sometimes and I just don’t get around to my WC, which is another reason weekly is good because if I skip next week it won’t kill me(or the tank)

[Tired]

It depends hugely. Feed your fish daily, feed your corals sometimes, and watch nutrient levels. If they're too low (under 5ppm nitrate and 0,03ppm phosphate), do fewer water changes. If they're getting high, or if you're low on calcium or magnesium, do more water changes. Every week to two weeks is about where most people fall, but it depends on the tank.

 

Again: do not let your nutrients get near or to zero. That will slowly kill your corals, in a way that often doesn't show up until they're in serious distress, and can encourage dinos. Dinos are about the worst pest you can have in your tank. 

[Clown79]

2 hours ago, Tired said:

It depends hugely. Feed your fish daily, feed your corals sometimes, and watch nutrient levels. If they're too low (under 5ppm nitrate and 0,03ppm phosphate), do fewer water changes. If they're getting high, or if you're low on calcium or magnesium, do more water changes. Every week to two weeks is about where most people fall, but it depends on the tank.

 

Again: do not let your nutrients get near or to zero. That will slowly kill your corals, in a way that often doesn't show up until they're in serious distress, and can encourage dinos. Dinos are about the worst pest you can have in your tank. 

100%

 

 

[ausram]

2 hours ago, Tired said:

It depends hugely. Feed your fish daily, feed your corals sometimes, and watch nutrient levels. If they're too low (under 5ppm nitrate and 0,03ppm phosphate), do fewer water changes. If they're getting high, or if you're low on calcium or magnesium, do more water changes. Every week to two weeks is about where most people fall, but it depends on the tank.

 

Again: do not let your nutrients get near or to zero. That will slowly kill your corals, in a way that often doesn't show up until they're in serious distress, and can encourage dinos. Dinos are about the worst pest you can have in your tank. 

Can’t stress how much I appreciate this statement. Sums up success (or failure) in this hobby.

[Jerad81]

My personal experience is don't get caught up on a set schedule. My tank is a little over a year old. I used to do water changes every week but I noticed my phosphate and nitrate levels never rose above 0 and my coral never died but also never grew. Since my nutrient levels never rose above 0 I made the mistake of stopping my tests and also stopped doing water changes completely for about 6 months. When I started testing my water again my levels were through the roof and my tests couldn't even read how high they were. Since I started focusing on getting the levels back under control everything in my tank appears to be significantly happier. I guess my point, and the biggest thing I've learned from this, is to do your tests on a set schedule and let the results dictate if you do a water change and how much. 

[Nano sapiens]

Some good general info here and I would add that no two systems are the same.  While higher nutrients might be what Reefer A's system runs best at, lower nutrients might be better for Reefer B's aquarium (within limits).  Over time, you will get a feel for what works best for your system not just by nitrate and phosphate levels, but also by observing coral health, coloration and growth and then you can adjust accordingly.

 

As an example and just one way to skin an onion (no cats were harmed in this post ), for my system which has always run PO4 'undetectable' and anywhere between 0.5 - 4 ppm NO3 when doing well, I have a set water change routine (5%, 2x/wk) which I've used almost exclusively for 12+ years and a base maintenance schedule to effectively deal with detritus.  If the system looks 'off' (and assuming all parameters look good), I first try adjusting my input (feeding) and/or export (detritus removal) to correct.

[jarviz]

On 3/14/2021 at 8:30 PM, Clown79 said:

Phos and nitrate shouldn't be 0, thats not beneficial. The tank needs both.

 

Waterchanges should be based on need. Each tanks needs are different.

 

I started with 10% every week but eventually my tanks did better with 10% every 2 weeks. My tanks ran very clean and weekly waterchanges led to no nutrients so I changed it. 

I understand that as tanks mature and get more stable, less water changes is doable and the tank will be fine... but why would a water change hurt, like in your case, even with a very clean tank?

Are you going from 1ppm nitrates to 0.9ppm? i don't see how that could be detrimental to the tank. 

[Tired]

When nutrients are too low, water changes keep them low. If they're too low, you want them to go up, and a good way to do that is to let them build up instead of taking them out. It's not that going from 1ppm nitrates to 0.9 is harmful, it's that keeping it at about 1ppm is potentially harmful. 

[Clown79]

5 hours ago, jarviz said:

I understand that as tanks mature and get more stable, less water changes is doable and the tank will be fine... but why would a water change hurt, like in your case, even with a very clean tank?

Are you going from 1ppm nitrates to 0.9ppm? i don't see how that could be detrimental to the tank. 

It is detrimental. Those nutrients are very much needed.

 

Why clean something that is already too clean? A sterile environment may look ultra pretty but there is 0 benefit to the life within that environment.

 

Its equivalent to starving everything. Pods, cuc, corals, macro algaes and in the end, that pretty starved environment ends up with nuisance algaes and dino's

 

 

I'd rather a tank with moderate to high nutrient levels, some algae than dying corals and dino's suffocating the life out of the tank.