reefertank
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How often are they needed, I know a lot of people say once a week but if my water parameters are good is that really necessary?
Water Changes
- Thread starter reefertank
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Water changes are largely dependent on the demands of your tank. You'll probably get dozens of different responses because everyone has different needs. After almost 3-years I'm doing a 30% water change every 3-weeks. It works for me.
CMO
Valuable Member
If your water parameters are good then there's no reason to do a water change IMO. The whole point of a water change is to remove waste (nitrate etc) and or replenish elements. If these are all in check then no reason to change the water. Although, absent ICP testing i'd probably still change water regularly since you wouldn't really know where you're with standard at home testing. Going on 5 months of no water changes in my tank with Triton which is simply a method of replacing elements and removing waste absent water changes. So depends on your set up really and whether you're dosing elements and controlling waste effectually with a method other than water changes.
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I shoot for 20%, or so, a month.
I do them for a few reasons. First, out with the bad and in with the good has always made sense to me. Second, and most importantly, they are cheap. A 50g bag of IO is about $12 and that can get me through a month. I can change a year of water for what a single triton test and a few chemicals cost.
Most people have no understanding whatsoever about phosphate binding with aragonite. Routine water changes, even when not seemingly necessary, can keep these levels lower than tanks that do not routinely change water. For example, I did an experiement where I added about 50 ppm of phosphate (yes, that much) and the aragonite absorbed it down to about 1/350th of that amount at about .16, which is low to most people... but 50ppm in the tank is not. Even though a 20% water change would only lower the water level to about .12, which does not seem like much, it would lower the rock level to about 40, which can be huge.
I do them for a few reasons. First, out with the bad and in with the good has always made sense to me. Second, and most importantly, they are cheap. A 50g bag of IO is about $12 and that can get me through a month. I can change a year of water for what a single triton test and a few chemicals cost.
Most people have no understanding whatsoever about phosphate binding with aragonite. Routine water changes, even when not seemingly necessary, can keep these levels lower than tanks that do not routinely change water. For example, I did an experiement where I added about 50 ppm of phosphate (yes, that much) and the aragonite absorbed it down to about 1/350th of that amount at about .16, which is low to most people... but 50ppm in the tank is not. Even though a 20% water change would only lower the water level to about .12, which does not seem like much, it would lower the rock level to about 40, which can be huge.
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reefertank
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This all sounds like good advice once everything few weeks is good for me, just doing them every week was getting old.
MaddReefer
Active Member
20% , once a month for me.
PatW
2500 Club Member
How often you do water changes like everything else in reefing depends on your system.
Water changes are not magic.
They serve two basic functions.
The first function is nutrient export. Now if you have other nutrient export systems in place like skimming, macro algae, and or carbon dosing, you may not need water changes for export.
The other main function of water changes is to replace depleted levels of important salt water chemicals. Most people test for ALK and Ca and dose those to maintain their levels. But dosing micro nutrients is tricky. There are a bunch of them and many do not have reliable tests. So by doing water changes, we hope that we are keeping these chemicals at adequate levels. Some people use a testing service and dose elaborate concoctions to replace these elements.
Oh a third purpose if water changes is to remove toxins. Some reef organisms use chemical war fare like many soft corals. You don’t want these things at high levels. You can remove them with activated carbon and some other methods.
Some people use such robust maintenance procedures that they can completely forego water changes.
The nice thing about water changes is they are simple and effective and cure a host of ills.
If you have decent husbandry and your tank is not high demand, you can probably get away with not so much in the way of water changes. If you have a high demand system and you are relying completely on water changes, you might have to do a bunch of them.
Water changes are not magic.
They serve two basic functions.
The first function is nutrient export. Now if you have other nutrient export systems in place like skimming, macro algae, and or carbon dosing, you may not need water changes for export.
The other main function of water changes is to replace depleted levels of important salt water chemicals. Most people test for ALK and Ca and dose those to maintain their levels. But dosing micro nutrients is tricky. There are a bunch of them and many do not have reliable tests. So by doing water changes, we hope that we are keeping these chemicals at adequate levels. Some people use a testing service and dose elaborate concoctions to replace these elements.
Oh a third purpose if water changes is to remove toxins. Some reef organisms use chemical war fare like many soft corals. You don’t want these things at high levels. You can remove them with activated carbon and some other methods.
Some people use such robust maintenance procedures that they can completely forego water changes.
The nice thing about water changes is they are simple and effective and cure a host of ills.
If you have decent husbandry and your tank is not high demand, you can probably get away with not so much in the way of water changes. If you have a high demand system and you are relying completely on water changes, you might have to do a bunch of them.
