Water change and top off

[frag!]

Hello everyone. I wanted to get some opinions on the need to do water changes even when I am adding 5 gallons of top off to my tank everyday. I have a calcium reactor setup on the tank and am wondering if I even need to do water changes. My total water volume is around 280 gallons with a low bioload, a melanarus, 6 bangai cards, royal gramma, shrimp, clams, 6 emeralds, and a lot of live rock. Does the salt itself go bad over time? I have had the tank setup around 18 months now and havent done a water change for 8 months or longer. Everything is looking and doing fine. I have a 6000 octopus protein skimmer with a 5 gallon waste bucket that doesnt seem to fill up very fast at all. All of my parameters are spot on. I appreciate any opinions on this. Thanks for your time and Happy Reefing.

 

[smiley28]

The main concern for any of the true experts is going to be wether or not depleted elements would be a big deal in your tank. So with that said do you keep coral? If not I'd say twice a year is sufficient.

Also thought I'd add that nutrient export would probably be your only concern if you're only running a fowlr tank.

 

[143MPCo]

IMO, top off water, assuming you are using RO/DI and that it's at 0ppm TDS is not adding any of the benefits you would get with water changes, and trace elements it may contain.

 

[nicodim55]

The main concern for any of the true experts is going to be wether or not depleted elements would be a big deal in your tank. So with that said do you keep coral? If not I'd say twice a year is sufficient.

Also thought I'd add that nutrient export would probably be your only concern if you're only running a fowlr tank.

I agree with you my tank my cal reading is at 820 and I'm still trying to figure out how to lower it

 

[143MPCo]

I would go at water changes in very small increments so as to not destabilize the system, nutrient export is also another reason for water changes.

 

[frag!]

I guess Im confused on what the calcium reactor is for then assuming it is supposed to add the trace elements to the tank? I currently have a candy coral, and xenias that have not done much lately. My xenias have spread 3 new stems but that is all. They have been in the tank for about 3 months now. Thanks for any replies.

 

[143MPCo]

IMO, CA reactors will make less of a contributions to the corals tissue than to corals skeleton, trace elements aid the coral tissue more.

 

[Randy Holmes-Farley Verified Community Expert]

I agree that a reactor won't necessarily add everything the growing organisms need, and it won't export anything.

I discuss water changes here:

Water Changes in Reef Aquaria by Randy Holmes-Farley - Reefkeeping.com

from it:

Conclusion
Water changes are a good way to help control certain processes that serve to drive reef aquarium water away from its starting purity. Some things build up in certain situations (organics, certain metals, sodium, chloride, nitrate, phosphate, sulfate, etc.), and some things become depleted (calcium, magnesium, alkalinity, strontium, silica, etc.). Water changes can serve to help correct these imbalances, and in some cases may be the best way to deal with them. Water changes of 15-30% per month (whether carried out once a month, daily or continuously) have been shown in the graphs above to be useful in moderating the drift of these different seawater components from starting levels. For most reef aquaria, I recommend such changes as good aquarium husbandry. In general, the more the better, if carried out appropriately, and if the new salt water is of appropriate quality.


Calcium and alkalinity, being rapidly depleted in most reef aquaria, are not well controlled, or even significantly impacted by such small water changes. In order to maintain them with no other supplements, changes on the order of 30-50% PER DAY would be required. Nevertheless, that option may still be a good choice for very small aquaria, especially if the changes are slow and automatic.

 

[Daniel@R2R Verified Admin]

IMO, top off water, assuming you are using RO/DI and that it's at 0ppm TDS is not adding any of the benefits you would get with water changes, and trace elements it may contain.

+1 to this. Top Off and water change are two totally different aspects of tank upkeep/maintenance and should never be looked at as related because their functions are so different. The primary goal of top-off is stability of the system (replacing evaporated H2O since to maintain the salinity and other parameters of your tank) while water changes are about replacing the trace elements that are being used by the system as well as nutrient export (though your nutrient export should arguably be carried out primarily through other means like a refugium and media reactors). So, I would say the question is really whether or not your system requires frequent water changes (regardless of the topping off with fresh RODI water since this has no effect on your systems need for trace element recoup or nutrient export...though it is good husbandry). Most systems do benefit from frequent water changes unless you are using some type of system for reef maintenance (Triton, DSR, etc.) that does not involve water changes.

I guess Im confused on what the calcium reactor is for then assuming it is supposed to add the trace elements to the tank? I currently have a candy coral, and xenias that have not done much lately. My xenias have spread 3 new stems but that is all. They have been in the tank for about 3 months now. Thanks for any replies.

If those are your only corals, then I'd remove the Calcium reactor until you have more coral (which will actually use up more calcium at a rapid rate that will be too fast to keep up with through water changes). Your system currently has no need of it.