Water Changes in Reef Tank: How Often and How Much?

[SkyReef]

BACKGROUND:
I have a bare-bottom, 75-gallon reef tank, with a sump operating at about 20 gallons. The net volume of water in the display tank is probably about 65 gallons, given the volume of displacement by the live rock. So I estimate my total water volume is about 85 gallons. I export nutrients by a protein skimmer and a DIY Waterfall, Algae Turf Scrubber. I dose the tank with B-Ionic Calcium and Alkalinity.

I don't have an algae problem and my water parameters are good: Salinity/Spec. Gravity: 1.024; High pH: 8.4; Ammonia 0; Nitrites 0; Nitrates 0; Phosphates 0.0; Calcium 500 (which, I know is a little high; I'll bring it down a little); and KH/Alkalinity 214.8.

I have two clownfish, a brown tang, a Kole tang, a Starry Blenny, two cleaner shimp, and three or four snails. I have lots of zoas, a brain coral, and a few, sps corals high up on the rock, under T5 lighting.

QUESTION:
How frequently would you recommend that I do water changes, and for each water change, how much? I use RODI water, made with a SpectraPure Max Cap 180 @ 0 TDS. I currently do a 5-gallon water change every week, but I was thinking about bumping it up to a 10-gallon water change every week. Would that be advisable, or would I simply be wasting valuable RODI water and marine salt mix?

What is your routine practice for water changes?

Thanks.

[patsfan1130]

20% every 2 weeks. Sometimes I am lazy and stretch to 3

[campos]

5 - 10% weekly

[cilyjr]

I have a 180 with roughly 240 total gallons. I do 25 gallons weekly. I used to do it less often and slightly bigger but I think I am seeing a happier reef since changing to smaller more regular changes.

[Sethjamto]

Smaller and more often would be the ultimate, but most recommend about 20% changes. I change between 15-20g's on my 90 every 2-3 weeks.

[phillrodrigo]

Since your running Bb it really doesn't have to be a specific amount. All the derititus will be easily seen so whatever it takes to get all of it out should be enough

[SkyReef]

Thanks, all. I'll go with 10% weekly.

[rogersb]

I have around 300g system and I shoot for 15-20g a week. That's 5% weekly. Since I do small % water changes I try to make the most of them and get as much detritus sucked out as possible as opposed to just removing water.

[TKCC]

I have the same tank specs and do between 5 - 7 gallon water change weekly. I'm a firm believer in consistency, so find a good water change schedule and stick with it as much as possible.

[Holyreefer]

i do 15 gallons a week on my 250

[Lateralus]

20 gallons every 2 weeks on a 140 gallon system. Thinking about going to 10 gals a week.

[Saltydrip]

I do 20-25% every 2 weeks

[Bpb]

I've got friends with RC totm caliber tanks that do once a year water changes, and others that do 20% weekly. No two tanks are the same. I personally do 10% every two weeks if only to replenish trace elements. I don't do much in the way of detritus removal because I run carbon, gfo, bio pellets, have a 3x tank rated skimmer, and run display macro. If I remove too much detritus the water will get too clean. I like to feed heavily too. Makes everything in the tank happy. Fish are fat and active and the sps are thriving.

[Spyderturbo007]

I try and do 5 - 10% every week. When I was doing 20% every 2 weeks, I wasn't very happy with the spike in parameters associated with the influx of new water. It might not hurt anything, but I wanted to be sure.

[terrypercula]

10% weekly for me. I could probably go months without it though.

[oshanickreef]

if you are dosing, i dont see a point in changing so often.. i would just test your magnesium and once it is low do a water change.

[chris.francis14]

I do a 5 gallon water change once per week on my 29 gallon... About 17.24%.

[whosurcaddie]

120 gallon tank 8 gallons every Saturday.

[Shan69743]

12-15g once a week on my 120g.

[Mussin]

I do 20gallons every month. I have a 90g and a 30g sump.

[SkyReef]

Wow! Such varied and insightful perspectives. All very helpful. Thanks, all. Great discussion!

[jimmy n]

Originally Posted by SkyReef

Wow! Such varied and insightful perspectives. All very helpful. Thanks, all. Great discussion!

Hey neighbor! I'm going to give continuous water changes a shot. I'm going to shoot for a gallon or so a day slowly over the course of the day. I'll let you know how it goes.

[cjcolvin]

I really like the small more frequent approach. It may be more often but your in and out quickly so to speak. I can get a 10% wc on my 55g done it about 30mins.

[ayionna06]

my total water volume is 300 gallons. I do roughly 40-50 gallons once a month

[SkyReef]

Originally Posted by jimmy n

Hey neighbor! I'm going to give continuous water changes a shot. I'm going to shoot for a gallon or so a day slowly over the course of the day. I'll let you know how it goes.

Interesting approach! Yes keep us posted!