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

[dbl]

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 people commented in the frequency thread but I thought it would be nice to see it in a poll. So let us know by responding to the poll above.

 

[Labridaedicted]

My. System volume is about 380 gallons and I try to do monthly changes that are the full volume of my 55 gallon bypass tank. Usually this is due to that being an observation qt tank that I just drain after I transfer the fish. When it's qt I bypass the tank with a valve and that way the qt is system water. Then I drain it and refill with new saltwater (after sterilization if necessary) and switch the valve so it is back on the system. So I guess my system varies between 380 and 325 gallons....

 

[nautical_nathaniel]

I usually try to do weekly or at most 10 day water changes on my IM Nano 20, I tend to change 5 gallons at a time since a 5 gallon bucket is easy to measure out in terms of how much salt I need. I feel like the larger regular water changes are more cost effective and simpler to do that trying to keep up with dosing schedules and stuff such as carbon media.

 

[bif24701]

I change out ~33%, 100+total gallons, every other week and sometimes more for my almost 300 gallon system with 180g display.

 

[aquaterra]

100gal total water volume
10 gal/ week (kinda?)

0.5l out every even hour at XX:15
0.5l in every even hour at XX:30

 

[Crabs McJones]

10%, about 6 gallons

 

[alex.mccann99]

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 people commented in the frequency thread but I thought it would be nice to see it in a poll. So let us know by responding to the poll above.

To further the discussion, I think there are downsides to changing out too much water. You lose the beneficial bacteria, also if you're not careful, can alter water parameters drastically within seconds. (Salinity, pH, temp, etc). I change a 5 gallon bucket, because it is very easy, two scoops of Aquaforest, suck out 5 gallons with my shop vac into a bucket, pour in new water. Done..

 

[dbl]

To further the discussion, I think there are downsides to changing out too much water...

I don't disagree. In the beginning, I was religiously changing about 20-25% every week. Once things really started to take off and grow, I quickly discovered I was changing too much and the water was too clean. I could never get N or P's to test anything but zero's. Now I do 20-25% about every 5-6 months, just so I feel good about doing something...lol.

 

[MaddyP]

I’m doing 1% (3000ml) daily via automation on my 75g.

 

[tdileo]

My tank is 46 gallons. I try to do a 10% water change once a month. I would like to get a better schedule of once a week or even every 2 weeks (asking for an RODI unit for Christmas) but for now I am only able to do it when I can get my parents to take me to my LFS and I haven’t gone in quite a few weeks as of now

 

[MnFish1]

To further the discussion, I think there are downsides to changing out too much water. You lose the beneficial bacteria, also if you're not careful, can alter water parameters drastically within seconds. (Salinity, pH, temp, etc). I change a 5 gallon bucket, because it is very easy, two scoops of Aquaforest, suck out 5 gallons with my shop vac into a bucket, pour in new water. Done..

Hi - interesting. What would you consider to be 'too much water' - ie, what percent weekly is good to change? If your water is matched for salinity.pH and Temp and presumably the salt used for replacement (barring errors in measurement) should be within a safe range what would change drastically? Lastly - given the ability of bacteria to rapidly increase if the correct chemicals are present for food - which beneficial bacteria are you talking about. (Lets say you do a 20% water change - you still have 80% of any bacteria present in the water)? I have seen this claim many times - that there is bacteria in the water (of course there is - tank water is not sterile) - but I am not aware of any data that it is not rapidly replaced with a water change, etc - or that fluctuating levels are harmful. Have always thought/heard/read that the vast majority of bacteria present in a reef tank is on the 'stuff'. Thanks for answering

 

[Arr6]

10-15%

 

[Labridaedicted]

Hi - interesting. What would you consider to be 'too much water' - ie, what percent weekly is good to change? If your water is matched for salinity.pH and Temp and presumably the salt used for replacement (barring errors in measurement) should be within a safe range what would change drastically? Lastly - given the ability of bacteria to rapidly increase if the correct chemicals are present for food - which beneficial bacteria are you talking about. (Lets say you do a 20% water change - you still have 80% of any bacteria present in the water)? I have seen this claim many times - that there is bacteria in the water (of course there is - tank water is not sterile) - but I am not aware of any data that it is not rapidly replaced with a water change, etc - or that fluctuating levels are harmful. Have always thought/heard/read that the vast majority of bacteria present in a reef tank is on the 'stuff'. Thanks for answering

My understanding is that the bulk of the bacteria is benthic so unless you're vigorously vacuuming, I wouldn't expect a large decrease in the bacterial content.

As long as the parameters are very close, you can do huge water changes. I've done 80 or more percent with close to matched parameters with no noticeable stress.

If done improperly, you could easily crash a tank with a large water change, though.

 

[Derek Clifford]

There should be another option like, I don't do WCs because the method I use make it unnecessary. There is a difference in somebody choosing not to do water changes because they just don't want to versus not doing them because the dose using a method.

 

[srad750c]

Water changes for me are crazy, I don’t do the same thing each time. I have a 90 gal with a lot of structure, 10 gal in sump. I may do 5 gals on week, 10 the next. I do 2 times a month. Doesn’t seem to bother my corals. I always adjust kH and Ca, if needed. I add aminos, trace elements, vitamin supplement and SeaChem Fusion 3x week. Getting doser next year.

 

[Scott.h]

I used to do 10-17% a week until I realized it was unnecessary. I quit completely. Now I send in a water sample to triton every few months and add elements accordingly.

 

[srad750c]

Hi - interesting. What would you consider to be 'too much water' - ie, what percent weekly is good to change? If your water is matched for salinity.pH and Temp and presumably the salt used for replacement (barring errors in measurement) should be within a safe range what would change drastically? Lastly - given the ability of bacteria to rapidly increase if the correct chemicals are present for food - which beneficial bacteria are you talking about. (Lets say you do a 20% water change - you still have 80% of any bacteria present in the water)? I have seen this claim many times - that there is bacteria in the water (of course there is - tank water is not sterile) - but I am not aware of any data that it is not rapidly replaced with a water change, etc - or that fluctuating levels are harmful. Have always thought/heard/read that the vast majority of bacteria present in a reef tank is on the 'stuff'. Thanks for answering

I have done a 15 gal changes with gravel vacuum 4 days in a row with no immediate detrimental effects on my 90. The problem came later and it took me almost a year to correct. My tank was too low in nutrients for my LPS, polys and mushrooms. They started dying off. I had a small Cyanobacteria outbreak in a small area of the tank and did those changes to get rid of it.

 

[srad750c]

I used to do 10-17% a week until I realized it was unnecessary. I quit completely. Now I send in a water sample to triton every few months and add elements accordingly.

I’m not that brave