Calcium Reactors - friend or foe?

[ckrhone]

if a calcium reactor is set up correctly, will it cause the ph to drop dramatically or not?

[cward]

Your tank ph will drop when you use a reactor for the simple fact that you are lowering the ph in the reactor to dissolve the media. How much you need to lower the ph in the reactor will depend on what type of media you use, because some media dissolves easier than others. The ph drop in your tank is due to the amount of effluent you dose from the reactor, based on the demand of your corals. If you do decide to set up a reactor, this (http://home.comcast.net/~jdieck1/reactor.html) site will help you dial it in.

[ckrhone]

I have just got a deltec reactor but have not yet set it up. I am concerned about ph because my ph keeps dropping to 7.7 in the morning and by adding kalkwasser each day is going up to 8.3 at the end. My calcium appears to be constant at 380-400 ppm but if i start using the reactor to replace the addition of kalkwasser, how do I keep the Ph up because if the calcium goes up, so will the KH won't it? this is at 10dkh.

[TwistedTiger]

Adding a reactor doesn't automatically mean your ph will drop, mine actually went up. It depends on your tank, my alk dropped significantly every day and saturated kalk couldn't keep up so the ph dropped. Adding a reactor stabalized my alk and my ph. You can still drip or topoff with unsaturated kalk to help maintain ph, I switched from 2 tsp/gal to 1 tsp/3gal and the ph of the mix is over 11.

[skylar]

No Ph issues here. I've been running a dual chambered unit from MTC for years. I like the dual chamber because it protects against any CO2 entering the system which could negatively effect the tank in many ways 1 of which is lowering the Ph - I never dose Kalk or anything. last time I test CA 480 - 500 Kh 8 - 10 Ph 8

[Boomer]

twisted

It depends on your tank, my alk dropped significantly every day and saturated kalk couldn't keep up so the ph dropped.

The pH drop is often due to CO2, the Alk can have very little to do with that. Even if the Alk was high the pH can still drop due to CO2. CO2 has no effect on Alk and Alk has no effect on CO2. Are you sure that pH drop was not also due to CO2 ? That all was due to high Alk demand ?

It is not that all reactor have a pH problem but most single chamber reactors do. This pH drop from CO2 is the reason behind dual chamber reactors.

ckrhone

You can cut back on the CO2, tweak it so the effluent pH is a liltle higher, thus reducing the amount of Ca++ and Alk. The kalk sup, with a slow drip, can be used to adjust for pH/CO2 and put back in the Ca++ and Alk lost from cutting back on the reactor.

More to read

A Guide to Using Calcium Reactors
http://www.reefkeeping.com/issues/2002-05/sh/feature/index.php





edit
I see sky posted when I did so there you go and my favorite reactor to boot MTC :D

[gillies]

"Set up Correctly" There lies the rub. Calcium Reactors are a big pain in the @ss! Liter Meter dosing CA & Alk, with a little Limewater for top off - now there is friggn simplicity!

[Boomer]

gillies you forgot to mention how pricy some reactors are ;)

[TwistedTiger]

<a href=showthread.php?s=&postid=7873303#post7873303 target=_blank>Originally posted</a> by Boomer
Are you sure that pH drop was not also due to CO2 ? That all was due to high Alk demand ?

I'm no expert for sure but I did the indoor outdoor aeration tests and it had almost no effect on ph. I added the reactor and maintain my alk at 11.0 and my ph swing went from 8.2-7.75 then to 8.15- 8.0 now. The only things I changed were adding the reactor and cutting way back on kalk. Before I was dripping saturated kalk and still having to add 2 teaspoons a day baking soda to keep my alk around 9.5 and it would drop below 8 in 24hrs so both ph and alk were never stable. Never had a problem with fish or corals even my SPS I just didn't feel comfortable with the numbers. Reactors are expensive but I don't find them hard to operate at all once you get it dialed in and it's much more maitanence free and stable. JMO

[Boomer]

I'm no expert for sure but I did the indoor outdoor aeration tests and it had almost no effect on ph.

No, not from this, from the CO2 going into the reactor. It lowers the pH of the effluent water, you know that, which lowers the pH of the tank due to all of the CO2 not being used, even if you have a high Alk at the effluent or in the tank. This is where the kalk drip comes in. The kalk reacts with CO2, "eats it up" and adjusts the pH so it does not fall, hopefully.

8.2-7.75 then to 8.15- 8.0

Yes, that is a much nicer pH stability :D I wish all people with reactors had this only without kalk. Dual chamber reactors will do this.

I guess my point would be this. The kalk drip you have or need is fixing the excess CO2 from the reactor. Some people need to, due to demands or the way the tank is run. If you stopped the kalk drip the pH would drop due to the CO2 coming from the reactor. Kalk is the #1 fixer for pH, not buffers. And it actually make buffers and removes CO2 at the same time.

Ca(OH)2==> Ca++ + 2OH

2OH + 2CO2==> 2HCO3- (buffer, bicarbonate, baking soda w/o the Na+)