Alkalinity issues

JurisHP · 02/09/2020, 05:29 PM

My Geo CaReactor is maintaining my Ca, but my Alk is not stable at all. I keep having to use buffer to raise it, but it only stays raised for a few days and then slowly starts dropping. Any ideas?

LobsterOfJustice · 02/09/2020, 06:43 PM

Turn up the output of the reactor (increase flow or lower pH depending on how you control your reactor). Ca is used much slower so it’s likely dropping as well, you just don’t see it in the short term as much as alk.

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bertoni · 02/09/2020, 06:58 PM

I suspect that you just need to tune the reactor to produce more effluent. The calcium probably looks stable due to testing limitations. The consumption rate is about 2.8 dKH per 20 ppm of calcium. Do you have some measurements you could post?

JurisHP · 02/09/2020, 09:05 PM

But if I increase the effluent, it raises the Ca Reactor Ph, which is always at around 6.91 which is where it should be so it doesn’t melt.

Vinny Kreyling · 02/10/2020, 11:36 AM

The Alk reading coming OUT of the reactor should be above 30.
If not you need more CO2 or a slower flow. Check by testing the effluent, you will need to use more than 1 syringe of fluid, just add the total up.

JurisHP · 02/10/2020, 12:40 PM

The CR ph is around 6.71. What do you mean I’ll need to use more than 1 syringe?

Vinny Kreyling · 02/10/2020, 05:25 PM

Yes, 1 syringe will not get you that high.

bertoni · 02/10/2020, 05:46 PM

Increasing the flow rate might allow you to add more carbon dioxide to the reactor, and thus possibly increase the dissolution rate. I am not an expert on calcium reactors, though. If the pH of the effluent is still very low, then a second chamber of media might be appropriate.

I agree that checking the dKH of the effluent might be useful. You can dilute it by a factor of 4 (three parts tank water to 1 part effluent) and measure. That might be easier than titrating full-strength effluent, although both approaches might work.

five.five-six · 02/10/2020, 06:28 PM

First thing I check when I have alk stability issues is MG. Without at least 1300 MG it’s very difficult to maintain alk and CA

coralcruze2020 · 02/10/2020, 10:37 PM

are you pushing water into the reactor (creating pressure) or pulling water? pressure in the reactor does some funny things to stability of output. took me a while to figure that one out.

02/09/2020, 05:29 PM	#1
JurisHP Registered Member Join Date: Sep 2008 Location: Philadelphia, PA Posts: 168	Alkalinity issues My Geo CaReactor is maintaining my Ca, but my Alk is not stable at all. I keep having to use buffer to raise it, but it only stays raised for a few days and then slowly starts dropping. Any ideas?

02/09/2020, 06:43 PM	#2
LobsterOfJustice Recovering Detritophobe Join Date: Jan 2004 Location: Cary, NC Posts: 7,443	Turn up the output of the reactor (increase flow or lower pH depending on how you control your reactor). Ca is used much slower so it’s likely dropping as well, you just don’t see it in the short term as much as alk. Sent from my iPhone using Tapatalk __________________ If it's worth doing, it's worth doing right. I remember when zoanthids were called things like "green" and "orange" and not "reverse gorilla nipple." Current Tank Info: 180g reef with all the bells and whistles

02/09/2020, 06:58 PM	#3
bertoni RC Mod Join Date: Mar 2002 Location: Mountain View, CA, USA Posts: 88,616	I suspect that you just need to tune the reactor to produce more effluent. The calcium probably looks stable due to testing limitations. The consumption rate is about 2.8 dKH per 20 ppm of calcium. Do you have some measurements you could post? __________________ Jonathan Bertoni

02/10/2020, 11:36 AM	#5
Vinny Kreyling Registered Member Join Date: Nov 2002 Location: Miller Place, NY Posts: 7,206	The Alk reading coming OUT of the reactor should be above 30. If not you need more CO2 or a slower flow. Check by testing the effluent, you will need to use more than 1 syringe of fluid, just add the total up. __________________ 250 gallon mixed reef, 2 Reefbreeder's Photon V 2, Deepwater BLDC 12, DAS EX-3 Skimmer, MTC mini cal, 2-3/4" Sea Swirls, Aquacontroller & 6 Tunze pumps.

02/10/2020, 05:25 PM	#7
Vinny Kreyling Registered Member Join Date: Nov 2002 Location: Miller Place, NY Posts: 7,206	Yes, 1 syringe will not get you that high. __________________ 250 gallon mixed reef, 2 Reefbreeder's Photon V 2, Deepwater BLDC 12, DAS EX-3 Skimmer, MTC mini cal, 2-3/4" Sea Swirls, Aquacontroller & 6 Tunze pumps.

02/09/2020, 09:05 PM	#4
JurisHP Registered Member Join Date: Sep 2008 Location: Philadelphia, PA Posts: 168	But if I increase the effluent, it raises the Ca Reactor Ph, which is always at around 6.91 which is where it should be so it doesn’t melt.

02/10/2020, 12:40 PM	#6
JurisHP Registered Member Join Date: Sep 2008 Location: Philadelphia, PA Posts: 168	The CR ph is around 6.71. What do you mean I’ll need to use more than 1 syringe?

02/10/2020, 05:46 PM	#8
bertoni RC Mod Join Date: Mar 2002 Location: Mountain View, CA, USA Posts: 88,616	Increasing the flow rate might allow you to add more carbon dioxide to the reactor, and thus possibly increase the dissolution rate. I am not an expert on calcium reactors, though. If the pH of the effluent is still very low, then a second chamber of media might be appropriate. I agree that checking the dKH of the effluent might be useful. You can dilute it by a factor of 4 (three parts tank water to 1 part effluent) and measure. That might be easier than titrating full-strength effluent, although both approaches might work. __________________ Jonathan Bertoni

02/10/2020, 06:28 PM	#9
five.five-six Registered Member Join Date: Mar 2007 Location: Corona Posts: 7,827 Blog Entries: 6	First thing I check when I have alk stability issues is MG. Without at least 1300 MG it’s very difficult to maintain alk and CA __________________ Originally posted by yellowslayer13: "I hate that hole" Current Tank Info: SCMAS Member 225 peninsula euroreef RS180 Apex 400W X 3 20k radiums / Spectra mixed SPS

02/10/2020, 10:37 PM	#10
coralcruze2020 Registered Member Join Date: Feb 2020 Location: NY Posts: 115	are you pushing water into the reactor (creating pressure) or pulling water? pressure in the reactor does some funny things to stability of output. took me a while to figure that one out.