Dumb wc question

[A Toadstool Leather]

Does doing lots of water changes compromise the stability of the tank. I understand that stability is key for growth. If I went from changing 5 gallons out of 30 to 10 gallons would the benefits outweigh the costs?

 

[DLHDesign]

First - not a "dumb" question at all. Quite a good one, in fact!

I'd guess that you're using water changes as part of your nutrient export plan (eg; getting rid of nitrates and such)? If so, then larger water changes will have more of an impact on this, of course.
You're also likely replacing trace nutrients at the same time. Depending upon how frequently you are doing water changes, you may or may not need to use more water for this purpose (if the nutrients aren't being significantly depleted at the 5gal volume, a 10gal change wouldn't help in this regard).

In either case - whether you're doing 5gal or 10gal - the key is to make sure you match your tank's salinity and temperature. If you do that, then it's unlikely that you'll do any harm to the tank. At the worst, you'll be "wasting" ~1/2cup of salt.
If you want to take a measured approach, I would suggest getting some test kits for various nutrients (and/or an ICP test). Find out where you are at in terms of your nutrient levels before your normal 5gal water change and after. If there's still more that needs doing (and the 5gal water change moved it in the right direction), then a 10gal change may make sense. But if the numbers are good (or didn't significantly move), then a larger water volume likely isn't needed.

 

[A Toadstool Leather]

First - not a "dumb" question at all. Quite a good one, in fact!

I'd guess that you're using water changes as part of your nutrient export plan (eg; getting rid of nitrates and such)? If so, then larger water changes will have more of an impact on this, of course.
You're also likely replacing trace nutrients at the same time. Depending upon how frequently you are doing water changes, you may or may not need to use more water for this purpose (if the nutrients aren't being significantly depleted at the 5gal volume, a 10gal change wouldn't help in this regard).

In either case - whether you're doing 5gal or 10gal - the key is to make sure you match your tank's salinity and temperature. If you do that, then it's unlikely that you'll do any harm to the tank. At the worst, you'll be "wasting" ~1/2cup of salt.
If you want to take a measured approach, I would suggest getting some test kits for various nutrients (and/or an ICP test). Find out where you are at in terms of your nutrient levels before your normal 5gal water change and after. If there's still more that needs doing (and the 5gal water change moved it in the right direction), then a 10gal change may make sense. But if the numbers are good (or didn't significantly move), then a larger water volume likely isn't needed.

Nutrients are fine, but im having issues with alk and ca. Dosing is costly so I would rather do wc. I match temp when I do wcs but not salinity.

 

[Flippers4pups]

Nutrients are fine, but im having issues with alk and ca. Dosing is costly so I would rather do wc. I match temp when I do wcs but not salinity.

Matching SG is critical and must be done each and every time. Alkalinity can be done cheaply by using grocery store baking soda. $.80 a box is cheap! Adding calcium and alkalinity at the same time can be done, in small systems with the use of kalkwasser (calcium hydroxide) pickling lime. Very cheap! A bag of “Mrs.wages” pickling lime at waly world is under $3.00.

 

[steelwrap]

Bigger water changes is just going to make your problem worse. Using less/more salt by not knowing salinity is just going to change your parameters every time you do a WC

 

[Phillyd1990]

Matching SG is critical and must be done each and every time. Alkalinity can be done cheaply by using grocery store baking soda. $.80 a box is cheap! Adding calcium and alkalinity at the same time can be done, in small systems with the use of kalkwasser (calcium hydroxide) pickling lime. Very cheap! A bag of “Mrs.wages” pickling lime at waly world is under $3.00.

+1 to the kalk. I got it from brs and have been using for 3 months with over half left. Its great until your tank becomes more demanding. Then a switch to 2 part may be in order

 

[beaslbob]

Nutrients are fine, but im having issues with alk and ca. Dosing is costly so I would rather do wc. I match temp when I do wcs but not salinity.

The only dumb question is the one not asked.

Dosing is not costly IMHO using the dr randy holmes Farley improved diy two part system. It uses calcium chloride, magnesium chloride, magnesium sulfate (Epsom salts), baking soda. It's been a few years since I bought some but calcium chloride is used to harden concrete in cold weather and a 50 pound bag was like $25 from a local redimix concrete place. Epson salts and baking soda from local drug/grocery stores. Magnesium chloride was the hardest to find but I found 50 pound bags for $30 from a local industrial chemical supplier.
50 pound bags will last literally for 10-20 years and I even gave them away at local club meetings.

you also might want to consider kalk using mrs wages pickling lime.

just me and my .02

 

[A Toadstool Leather]

+1 to the kalk. I got it from brs and have been using for 3 months with over half left. Its great until your tank becomes more demanding. Then a switch to 2 part may be in order

How do I calculate how much kalk or 2 part to add into my wc water?

 

[saltyfilmfolks]

Constants wc are stable becuse the water is all at a constant parameter coming in.
The reduction of nutints is minimal as the vol changed is quite small if you desire.
I'm short, the tank parameters begin to more reflect the parameters of the new water.

 

[steelwrap]

You want to dose the tank not the WC. You want the salinity the same in tank and water change water. Do you have any way to check the salinity? http://reef.diesyst.com/chemcalc/chemcalc.html

 

[reefndude]

First thing you need to out is rate of consumption. You may need to supplement. If you do start on the low end scale of using kalk. I believe it's 1 tbs per 5 gallons of fresh water

 

[Phillyd1990]

Before you start kalk i would get your levels where you want them. Kalk mostly mantains things where you want them.

 

[A Toadstool Leather]

You want to dose the tank not the WC. You want the salinity the same in tank and water change water. Do you have any way to check the salinity? http://reef.diesyst.com/chemcalc/chemcalc.html

I have a refractrometer I use to check salinity, and calibration solution.

 

[A Toadstool Leather]

First thing you need to out is rate of consumption. You may need to supplement. If you do start on the low end scale of using kalk. I believe it's 1 tbs per 5 gallons of fresh water

Since I do a wc weekly I will measure weekly consumption first.