Water Changes

[CavalierReef]

I recently switched from Reef Crystals to Tropic Marin Classic salt. I have religiously done a 5 gallon water change during the 8 months the tank has been running. My 32 gallon Biocube has 26.3 gallons of water so that represents a 19% water change. Is that too much? Tropic Marin instructions state that: "Never change more than 10% of total water volume". So I should be doing 3 gallon water changes? Sounds good to me to save some money. But why? Responses appreciated. Thanks.

 

[Dbichler]

I feel water changes are dependent on nutrient levels. On bigger tanks full of hard corals you would have to worry more about depleting alk cal and mag. On a bio cube you wouldn’t have as much demand. They probably only suggest 10% because you don’t change those numbers as drastically as you would with a large water change.

 

[Timfish]

Is that weekly, biweekly or monthly water changes? I generally do weekly water chagnes and target 20% to 30% a month. If you're doing weekly water 19% changes I'd cut back to 5% - 10%.

(As an aside, you seem to like exact numbers. In my experiences, trying to be exact with a reef full of variables that can't be measured and are being manipulated by all the life living in it is an excersize in frustration that will ultimately lead to burn out. Just my 2 cents. )

 

[CavalierReef]

Thanks for the responses. Timfish, I'm not really a precise number guy. I do think it's important to know the actual volume of water in your tank. The reason for my question was that a company that is the business of selling salt is

advising the consumer to use less of their product than they they might otherwise use. The question (to me) remains: what is the downside of making a water change of more than 10% with Tropic Marin Classic (or any other salt)??

 

[Timfish]

I can't speak to Tropic Marin's specific reasoning but from what I've read and my own experiences with decades old systems more or bigger is not necessarily better. Depending on the problem a ssytem is having large water changes might exacerbate a problem if it's pushing already high alkalinity higher or if the microbiota have been disrupted and a large water change is further reducing the healthy stuff by dilutuion. This later situation we can only now begin to test for (see AquaBiomics posts) but my own experiences fixing problems with small water changes with water from a reef system not having issues after large water changes failed to do anything has certainly shown me they may not always be useful.

 

[lpsouth1978]

My guess for their reasoning is simple, to reduce large parameter swings. Changing large % of the water WILL likely cause larger swings in parameters and nutrients. By performing smaller water changes the system will remain more stable. This is similar to having an AWC system in that the system does very small water changes daily, keeping the system as stable as possible.

This is why I try to do 10% weekly water changes on my systems instead of larger monthly, or bi-weekly changes.

 

[SPR1968]

The 10% you mention is a general good guide so that the water parameters aren’t affected to much in the system. Stability is the key and that’s it really and probably why the recommend that approach

You can do larger changes if you need to for example if you have a problem

 

[Reef.]

I recently switched from Reef Crystals to Tropic Marin Classic salt. I have religiously done a 5 gallon water change during the 8 months the tank has been running. My 32 gallon Biocube has 26.3 gallons of water so that represents a 19% water change. Is that too much? Tropic Marin instructions state that: "Never change more than 10% of total water volume". So I should be doing 3 gallon water changes? Sounds good to me to save some money. But why? Responses appreciated. Thanks.

I think if you keep in mind why you are doing water changes you can answer this yourself.

To keep nutrients down, if your nutrients are not increasing then you could try smaller changes.

Replacing elements in the water, if you don’t have a sps tank then again you could try less.

TM I believe suggest 10% because more will change your parameters too much, such as alk and ph etc so the fish and corals could be affected, 10% does seem low though, so keep that in mind when making changes.

 

[mike550]

I change 10% each week on a 120G. My thought is that 10% doesn’t make big changes to the overall water profile but does “freshen“ things up.

 

[ShepherdReefer]

I say find out what works best for your application and stick with it. We was doing a water change on the 1st and 15th of each month but recently changed to every Tuesday at 10%. Working much better.

 

[CavalierReef]

Thanks for all the responses. Yes, I will have to figure out what works best for my tank as I always attempt to do. I did a 3 gallon water change and I will see how everything reacts. If it reacts as well as it did to a 10 gallon IO Reef Crystals change, then if course I'll stick with it. I'm not fighting any kind of problem here. I'm merely attempting to maintain a healthy environment for my corals and fish. (or is it "fishes")

 

[redeyejedi]

I do a 5% water change on my 130l tank roughly every two days. The reason for this is i dont dose so to keep my alk cal and mg stable that way. As said above it all depends on the system and the person looking after it.

 

[CavalierReef]

I do a 5% water change on my 130l tank roughly every two days. The reason for this is I don't dose so to keep my alk cal and mg stable that way. As said above it all depends on the system and the person looking after it.

I don't dose either to maybe smaller and more often is an appropriate protocol for me too. Thanks for sharing.

 

[redeyejedi]

I don't dose either to maybe smaller and more often is an appropriate protocol for me too. Thanks for sharing.

Your welcome. Works for me. I use coral pro salt so it bumps the alk up by .3 each time.