Geo 6x12 issues and questions

[jdieck]

OK I think the drop might have been the large top off. Se iff tomorrow it is still at around 3.25, if it drops then we will set it to were it was 6.4 to 6.6 and increase the bubble rate by 10%.

Now that we know that you are looking for a PH of between 6.5 and 6.6 when ready to set up the controller as a back up only what will will do is try to adjust the bubble rate to maintain a PH of 6.5 to 6.6 without the use of the controller.
Note that without the controller turning the CO2 on and off the reactor PH will go up and down a littlebit following the cycle of the tank PH, in other words as the tank PH drops at night the reactor will operate a little lower say 6.5 and during the day a little higher 6.6. That is OK and does not affect the total daily alkalinity addition.
There will be two ways to do it.
If the needle valve is precise enough to maintain a stable bubble rate then we can lower the range of the controller to 6.3 to 6.5 so it will stay on whne our bubble rate targets 6.55 and close if by any chance the PH drops too much (6.4) then will adjust the bubble rate slightly at a time to maintain the target between 6.5 and 6.6 If this proves difficult the valve is not precise enough, in that case we readjust the controller back to 6.4 to 6.6 and still try to set the bubble rate as close to 6.5 as possible. In this later case the controller may or will still turn on and off but will be so infrequently that it will work much less.

 

[aquaconnect]

Okay, I'll test it tomorrow again and get back w/you. Thanks again so much!!!!

 

[aquaconnect]

Tonight tests are 8.1/8.2 ph and 3.15/8.82 alk. So I think we are ready, what should I do now? Also, if I top my tank off is it okay to start adding baking soda to the top off water, or do I still wait to do that until we get it dialed in?

 

[jdieck]

<a href=showthread.php?s=&postid=10150600#post10150600 target=_blank>Originally posted</a> by aquaconnect
Tonight tests are 8.1/8.2 ph and 3.15/8.82 alk. So I think we are ready, what should I do now? Also, if I top my tank off is it okay to start adding baking soda to the top off water, or do I still wait to do that until we get it dialed in?

Once dialed you will not need baking soda for normal addition, just top off pure Ro/DI water.
Once in a while you may need to make an alkalinity or calcium adjustment but it is better to do it in a single shot than adding any continuously via any other method.
For example, right now when the reactor is set, if you want an alkalinity higher than the 8.8 you have now (say increase to 10.0) you can use the reef chemistry calculator to determine how much baking soda powder you need to dissolve in a cup of water and just pour it in. Similarly once the reactor is set you want to test your calcium and use calcium chloride (TurboCalcium) the calculator will also help you determine how much powder to use to make the one time adjustment.
http://home.comcast.net/~jdieck1/chem_calc3.html

Regarding the reactor I think it is close to were you want it if not there already.
As described above to use the controller as back up.
Set the controller to a lower range of 6.3 to 6.5 so the CO2 is always open at your required range of 6.5 to 6.6 but close the needle valve to reduce the bubble rate slightly so the PH neither drops not increase and stay between 6.5 and 6.6.
If after several adjustments you find that the bubble rate is not stable enough to be able to keep that range without the controller because the nedle valve is not that accurate then we will need to use the controller back to 6.4 to 6.6 but with the bubble rate adjusted so close to maintaining that 6.5 that the controller although operating will not turn on and off too often. (once evry half an hour or so will be OK.)
Keep testing the tank every 24 hours.
This is also a good time to test for Calcium and Magnesium and make a one shot adjustment if necessary.

 

[aquaconnect]

Good deal. I set the controller at 6.3 and 6.5, and adjusted my dkh and calcium. So far since you last posted and I adjusted, my ph has remained between 6.52 and 6.58 in the reactor. Thanks so much. I'll test daily for a while, and report back some info, or if I run into a problem and need some extra help. Thanks again so much! Your reef and website are awesome! Cheers

 

[jdieck]

Thanks and good luck!, Enjoy!

 

[aquaconnect]

UPDATE: Well my calcium is now holding over 400 pretty easily, ph 8.1. However, I am having some issues w/my dkh. I got it boosted up to about 5.0/14, but over the past 4 days it has dropped to about 3.8. The controller holds a constant 6.54 on the money all the time. Should I increase the effluent drip rate a bit? Right now it is at 36mil's/min consistantly.

 

[jdieck]

If the alkalinity goes to high (5 meq/lt) you will precipitate some.
Because you shall try keeping your alkalinity between 3.5 and 4.0 (exceeding 4 is not recommended) do not make any adjustments yet, see if it stay between 3.5 and 4. If it continue dropping then I would prefer to try lowering the reactor PH a bit (6.5) even if you need to lower the controller to 6.25 to 6.45

 

[aquaconnect]

Good deal. I got a little out of control w/my baking soda when I calculated my top off the other day, that's the only reason it was so high, but I will monitor it. I just thought maybe it wasn't maintaining. Thanks again!

 

[jdieck]

Actually there should not be a need to add baking soda in your top off. Further more it can alter the balance between calcium and alkalinity.
Remember that a calcium reactor is not to add calcium, IMO they should be called alkalinity/calcium reactors as they add both in the same proportion corals will use them in their skeleton.
If you are adding much you can stop that addition just by increasing the effluent a bit, say to 45 -50 ml/min while also increasing the CO2 bubble rate to maintain the 6.5 to 6.55 PH.