Water change question

[Djplus1]

Is there an optimum amount to change percentage wise on a weekly basis? I know a bunch of you change monthly or every couple weeks, but since I do it weekly, I'm wondering if I should shoot for 10% or more/less? I've been going back and forth from 10%-25% give or take every week for over a year now.

[YHSublime]

Tom shared some research showing a big water change once vs. smaller and more often was more effective. On the phone, I'll see if I can find it when I hit the desktop.

 

I know that doesn't answer your question, but it's a good read. I've tried to practice less more often with food, and more, less often with water changes, fwiw.

[Djplus1]

Tom shared some research showing a big water change once vs. smaller and more often was more effective. On the phone, I'll see if I can find it when I hit the desktop. I know that doesn't answer your question, but it's a good read. I've tried to practice less more often with food, and more, less often with water changes, fwiw.

More effective for what specifically? Generally, replacing 50% of water once is better than 10%, 5 days in a row if you're trying to reduce nitrates or some other contaminant, but I'm just talking normal water changes for maintenance.

[Origami]

Removing pollutants.
 
Here's one reference from a 2005 article written by Randy Holmes-Farley.
 
The whole thing is worth reading, but scroll down to the section titled, "Size of Water Changes: A General Case" for the specific case that Isaac is citing.

 

The section above that will probably provide more of the information that you're curious about.

[Origami]

An obvious benefit of smaller water changes, though, is stability of parameters. That can't be stressed enough. It's one reason that some people perform many small (automated) water changes per day. You use more salt in the long run, but the benefit of that added cost is stability.

[tomtom2245]

I personally do a ~10% change every 7-10 days. 

[scott711]

An obvious benefit of smaller water changes, though, is stability of parameters. That can't be stressed enough. It's one reason that some people perform many small (automated) water changes per day. You use more salt in the long run, but the benefit of that added cost is stability.

 

+1

[Jason Rhoads]

I shoot for 5-10% weekly --I usually only do 5%.  I also have a very small bio-load in my tank (11 3" fish in a 100g system). Personally, I like the smaller WCs because of the added stability, but if the tank has some other issue I advocate doing larger.

 

"The solution to pollution is dilution"   

[sen5241b]

I wait a couple months then do a 50% with change out water that is dosed with cal and a bit of mag but NOT alk. My cal stays high for 2 months. The 50% has never caused any issues.

Edited December 30, 2013 by sen5241b

[Djplus1]

I shoot for 5-10% weekly --I usually only do 5%.  I also have a very small bio-load in my tank (11 3" fish in a 100g system). Personally, I like the smaller WCs because of the added stability, but if the tank has some other issue I advocate doing larger.

 

"The solution to pollution is dilution"

 

So even 5% weekly does the job, huh? I was thinking my 10% was cutting it a little close. Maybe I'll stick with the weekly 10% on all three tanks. That works out to around 15gallons a week which is fine with me.

[MBVette]

I usually do 20-30% monthly or sometimes wait even longer.  but i have been known to get pretty lazy if everything is growing and looking good.

[smallreef]

I've been slacking...but I used to do a 10% every other week.....

I'm jumping back on that schedule to keep up with my maintenance...

[Orion]

Fwiw it's worth Mark Callahan (Mr. Saltwater Tank) advocates 5% weekly water changes.

 

Couple of reasons -

1. Stability. A weekly water change is much more stable than a monthly or bi-weekly one

2. If you have a 90 gallon system you are much more likely to change 9 gallons of water a week than 18 gallons every two.

 

[pizzaguy]

Haha. I've been changing 50 gallons twice a week on a 150 gallon system. Nitrate issues.

[YHSublime]

2. If you have a 90 gallon system you are much more likely to change 9 gallons of water a week than 18 gallons every two.

 

I disagree with this, but I'm part of the bucket brigade. I try to do as much as possible when I can, as I'm probably one of the few BB members who still uses the method on a larger system. My next big reef project will be making this easier with pumps.

[BowieReefer84]

I do 15%-20% once a week right now.  3-4gal 

[Squishie89]

I do 15-20% a week on my 90g system. I make up 20 gallons of water, 10 cups of salt, simple.

[londonloco]

I do 20% on my fw systems, and 10% on my reef weekly.  Tho you can't fight the "math" in dilution figures, I find my fish, plants and coral do much better with weekly wc's.  

[ctenophore]

I do 1 gallon every 6 hours, or 4 gpd, or ~120 gal/mo, on my ~800 gal system and it hasn't looked as good since I set it up back in 2007.  I am definitely loving automatic changes.  I still do bucket changes on my son's nano located at the other end of the house but I am planning on running poly tube through the attic to put it on an auto system too.  I wouldn't ever do a new tank again without planning for an auto changer in the design (more importantly, a route to drain waste water away).

[lnevo]

I wouldn't ever do a new tank again without planning for an auto changer in the design (more importantly, a route to drain waste water away).

That is my one biggest regret with my current setup. Something I need to correct one day.

 

[Jason Rhoads]

So even 5% weekly does the job, huh? I was thinking my 10% was cutting it a little close. Maybe I'll stick with the weekly 10% on all three tanks. That works out to around 15gallons a week which is fine with me.

 

Yep, 5% is good for my system. Find what works for your stocking/feeding plan.

 

I don't get hung up on total % changed. I think it is a fallacy to think that you must change x% of your water or your tank will suffer. As with most things in life it all depends on your situation. I am looking to up my total system water volume by 60 gallons, but will still only do 5g water changes. This is because my fish load and feeding will remain basically unchanged. I do try to siphon as much as I can when I make my weekly changes. 

[Coral Hind]

Yep, 5% is good for my system. Find what works for your stocking/feeding plan.

 

I don't get hung up on total % changed. I think it is a fallacy to think that you must change x% of your water or your tank will suffer. As with most things in life it all depends on your situation. I am looking to up my total system water volume by 60 gallons, but will still only do 5g water changes. This is because my fish load and feeding will remain basically unchanged. I do try to siphon as much as I can when I make my weekly changes. 

I totally agree. Test your water and find a volume and frequency which works for your own tank.

[smallreef]

I disagree with this, but I'm part of the bucket brigade. I try to do as much as possible when I can, as I'm probably one of the few BB members who still uses the method on a larger system. My next big reef project will be making this easier with pumps.

I bucket it too Isaac,lol

Though I am less than 5 feet from my tub to my tank I still have to haul them through the doorway to the front of the stand,lol

[AlanM]

I bucket it too Isaac,lol

Though I am less than 5 feet from my tub to my tank I still have to haul them through the doorway to the front of the stand,lol

Why not get a couple small powerheads, a DJ powerstrip, and 10 feet of tubing and throw the buckets away?

[YHSublime]

Why not get a couple small powerheads, a DJ powerstrip, and 10 feet of tubing and throw the buckets away?

 

For me the issue is that my water mixing station is not near an outlet. It's the coat closet of our apartment, and I've got to run a powerstrip through the door and leave it open whenever I want to mix up 55 gallons. It's a pain, but nobody knows it's there.