Too much water change a bad thing?

[Mattman1977]

On my 24 gallon with only 3 fish, I started with 10% per week to 20% every 2 then I have had issues of 0 phosphates and nitrates of 10, which led to cyano. Now I siphon the water out through a filter sock, I then put then siphoned water back in the tank. I am currently manually dosing phosphates to try and get a reading aswel, my once dead montipora digi is growing again, and my pale frogspawn is now green again and colours are looking better. I filter the water out and put it back in every 2 weeks and top up what I have wasted with fresh NSW.

On my sons 7 gallon I only do a 20 % change every 3 months.

I think depending on the individual system you should only change water if needed, and not because a week has gone passed. Both tanks are now over 3 years old, no sumps or skimmers or refugiums, and the one I have had the least problems and do the least amount of work to is the 7 gallon.

I’m in the process of starting up a 24gal jbj cube aio and planned on softie with a few lps, devils hands and have 2 beauty colonies of Duncan’s. Well was thinking strongly about a awc dos system but after reading this I might hold off on ordering it. Can always add it later if need be. Planning only biweekly sand vacuuming of roughly 3-6 gals. I’ve had issues with low nutrient in past aquariums so trying to avoid that this time

Matt

 

[H2ODude]

As a newcomer to this hobby, and trying to learn all I can here, this thread is a great example of why it'd hard to get comfortable learning it. There are obviously no wrong answers here, but THEY'RE ALL OVER THE PLACE! So I'll just adopt 10% a week and see what happens. Y'all have a great day!

 

[SMB]

If the purpose of the WC is to reduce nutrients (ie for GHA, QT tank etc.) then probably never a bad thing. You could argue frequent small volumes vs. one large 50%+ change, but you are correcting a specific observable/measurable problem.

If the WC is for general maintenance then I don't know the answer. Does WC restore miro elements that are not being dosed? If so there has to be some minimum percentage of water volume that has to be changed per day/week/month
to maintain those elements otherwise the WC is of no value? There are bio wastes that accumulate that are not managed by bacteria filtration or protein skimming so in a closed system it would seem that some degree of new water turn over would be necessary.
Personally I change 10-15% weekly. Tank seems to do well (5yrs) without nuisance issues but I don't keep anything overly challenging.

 

[Ashish Patel]

There is no right or wrong answer here. I've never done a waterchange under 1 month and not sure how someone can do this kind of work when 1 month comes around quickly. I spend the time cleaning all my pumps monthly, Testing frequently, and monitoring treads. I can honestly conclude after 22 years in the hobby your wasting alot of water and salt by doing them frequently. New hobbyist should be doing 1 time per month and only if they are paying attention to their source water otherwise they could be adding chloramines, and other contaminants. Trust me I've been that guy.. 11 year old hobbyist using strait tap water haha

 

[SMB]

There is no right or wrong answer here. I've never done a waterchange under 1 month and not sure how someone can do this kind of work when 1 month comes around quickly. I spend the time cleaning all my pumps monthly, Testing frequently, and monitoring treads. I can honestly conclude after 22 years in the hobby your wasting alot of water and salt by doing them frequently. New hobbyist should be doing 1 time per month and only if they are paying attention to their source water otherwise they could be adding chloramines, and other contaminants. Trust me I've been that guy.. 11 year old hobbyist using strait tap water haha

So what % volume do you change? If it is a large volume isn't that more disruptive to the system (and really nothing saved in cost) and if it is a small volume, what's the point?

The real question is what are we actually accomplishing with a WC and can you make some kind of educated calculation as to % WC based on the bioload (and species) in ones aquarium. If not than WCs are just based on what you observe in your own aquarium and your experience. So each start up will always be by the seat of your pants.

 

[Fishurama]

As a newcomer to this hobby, and trying to learn all I can here, this thread is a great example of why it'd hard to get comfortable learning it. There are obviously no wrong answers here, but THEY'RE ALL OVER THE PLACE! So I'll just adopt 10% a week and see what happens. Y'all have a great day!

This is why I wish the thread was closed with my response lol. Here are polls from the same site(r2r) with hundreds(800ish on one 500ish on the other) of votes. Most popular is 10-20 percent weekly.

This was an older poll thread on here, 10 to 20 percent is the most common, and generally, if all your water is mixed properly, there is no such thing as "too much of a water change" as some people do a 6 month to yearly 50 percent change without issue. Just as long as what you are mixing/getting matches your tank all is good.

Poll: What Percentage of Water Do You Change During WC?

Yesterday’s poll topic was water change frequency, found here. The majority of people responding indicated they do weekly water changes, followed closely by every other week/twice per month. Let’s follow up with how much water you actually change, if you do in fact do water changes. Several...

www.reef2reef.com

Also weekly seems to be what most prefer.

Poll: Water Change Frequency?

Water changes - a topic discussed in great detail throughout R2R. Should we do them and why? How often? How much at one time? The questions go on and on. Well this thread/poll is meant to answer only one of those questions - How Often? I'm more curious as to the frequency of those that...

www.reef2reef.com

I personally do 20-25 percent changes on my 120 gallon weekly.

 

[SMB]

To play the devils advocate, what are those numbers based on? While the majority do X% weekly, is that based on any actual science?
If not do we ever have to have this discussion again?

 

[Nicholas Dushynsky]

I used to buy pre made salt water and done a 10% water change on a 180litre tank every week then changed it to 2 weeks as the cost got silly. I now have 3 nano tanks a 7,13 and 24 gallon. All 3 are running on NSW which I collect and have used for over 2 years, the first year I went back to 10% a week.
I now only do a water change for maintenance really, so only when I feel its necessary as I only have a low stocking fish wise and only feed minimally. I feel that doing the weekly water changes with my low stocking bottomed out my phosphates on the larger 2 of the tanks and caused cyano. This caused my montipora digitata to die. I now don't do a percentage change on those two tanks, just maintenance consistent of just cleaning the glass, syhoning the sand out through a sock and put the water back in, then top up with fresh NSW. I also have to dose phosphates to get a reading. I am trying to get them back to where they were. My colours are better and my once dead digitata are growing again from the few polyps that were left. So this system is working for me, so far. I'm 3.5 months in to this.

With the frequent testing and dosing of alk, calcum and magnesium manually on the 2 smaller tanks and with kalkwasser in my ato on the larger. I didn't see the point of paying to add those elements to only dilute it a week later.

Don't get me wrong, a regular water change can and will work on many tanks, I feel this is something that is sort of old school, and was taught to me when I started reefing about 14 years ago, of which I followed for many years. The route I'm going, is only down to issues I have faced and the recommendation of people here on R2R to keep levels of nitrates and phosphates up and not to bottom them out again.

 

[hart24601]

I have never seen evidence too many water changes are a bad thing. That is of course if temp, salinity and alk match or are at least close. As Brandon said many picos change 100%, many with sps that have been going for years. I suspect we might have some bias to say ‘too many water changes are bad’ as a subconscious way to justify not doing them.

If a tank needs them or not is another question. I personally have auto waterchange on my system and consider it extremely valuable

 

[Buffalou]

I have auto set up to pull one gallon out and add one gallon daily, I have a 100 gal system so I change about 30% monthly if my math is correct. Easier on me and on my tank, it also allows me to be dead on with my parameters keeping things as stable as possible. I used to do the 15 gallons all at once every two weeks, but then it would take a couple days to get my levels back to their norms. So I find it easier doing daily changes.