What's making my Kh (Alk) keep going up?

[porpoiseaquatics]

Ok....I've been chasing this issue for some time now and frankly, I'm tired of trying to figure it out on my own so I'm looking for some advice.

Here's today's parameters using a Red Sea Pro Test Kit.

CA: 390
Mg: 1120
Kh: 14
pH: 8.2
Sal: 1.025
Temp: 80

Salt Brand: IO

I have a CaR online that is set to start at 6.40 and kick off at 6.50. Occasionally it misses the mark and kicks on at 6.36 and off at 6.55 but that's pretty rare. I've just started dosing liquid calcium (BRS) to get the CA number up to 440. Mg has increased on the same plane as CA has increased so I'm not dosing Mg thinking it will increase as well. I should probably also mention that my drip rate from the CaR to the sump is about 5 drops per second. I've heard of people opening this wide open but I don't know what affect that will have.

What the heck is causing my Kh (Alk) to spike and how can I best control it? This is the whole reason I went to a CaR as I understood that it would keep these things in alignment on it's own.

 

[thanhreef]

I have stopped using reactor since 2012. I still have this link in my bookmarks

I copied and pasted here.... http://www.reefkeeping.com/issues/2002-05/sh/feature/">full article</a>. Hope this helps

"....[B]Out of Balance[/B]

Another common problem when setting up a calcium reactor is getting a correct balance between calcium and alkalinity. A common complaint is as follows:

"I have an alkalinity of 3.5 mEq/L (10 dKH), but my calcium level is only 320ppm. I have tried adjusting the reactor, but cannot get the calcium level to rise without the alkalinity going too high."

A calcium reactor may be described as a 'balanced' calcium / alkalinity additive. Basically, this means that it adds calcium and alkalinity to the tank in the same ratio as is used by our corals during the process of calcification. Simply put, it is not possible to change the calcium level without the alkalinity being affected also in a defined manner..."

 

[porpoiseaquatics]

thanhreef;1064962 wrote: I have stopped using reactor since 2012. I still have this link in my bookmarks

I copied and pasted here.... http://www.reefkeeping.com/issues/2002-05/sh/feature/">full article</a>. Hope this helps

"....[B]Out of Balance[/B]

Another common problem when setting up a calcium reactor is getting a correct balance between calcium and alkalinity. A common complaint is as follows:

"I have an alkalinity of 3.5 mEq/L (10 dKH), but my calcium level is only 320ppm. I have tried adjusting the reactor, but cannot get the calcium level to rise without the alkalinity going too high."

A calcium reactor may be described as a 'balanced' calcium / alkalinity additive. Basically, this means that it adds calcium and alkalinity to the tank in the same ratio as is used by our corals during the process of calcification. [B]Simply put, it is not possible to change the calcium level without the alkalinity being affected also in a defined manner[/B]..."[/QUOTE]

Then based on that statement, it wouldn't matter how Ca is introduced (whether from dosing or from a CaR), Alk will still rise.

 

[cment]

jeff, maybe a bad ALK test kit? Have you tried to use another brand or taken a sample to a local sponsor to confirm your number?

 

[porpoiseaquatics]

cment;1064967 wrote: jeff, maybe a bad ALK test kit? Have you tried to use another brand or taken a sample to a local sponsor to confirm your number?

I wondered about that myself so I tested with another Red Sea Pro kit as well as with a Sera Kh kit and got the exact same reading from all 3.

 

[jvb89]

Have you tried reducing the CO2 bubble rate to run the pH in the reactor a bit higher like 6.7-6.8? An article I read in reefkeeping magazine was talking about if your alk tends to keep rising that you should do this.

 

[reeferman]

exactly.decrease the bubble rate or raise the set point.you are dissolving the media too fast.decreasing bubble rate or raising the set point will dissolve less media making the effluent less saturated

 

[porpoiseaquatics]

reeferman;1064989 wrote: exactly.decrease the bubble rate or raise the set point.you are dissolving the media too fast.decreasing bubble rate or raising the set point will dissolve less media making the effluent less saturated

Ahhhhhh....this very well may be the issue. I was looking at the cycle graph and it appears that the regulator kicks on about every 30 mins and it doesn't take long for it to hit the "off" set point.

 

[grouper therapy]

And with such high alk you are probably beating down the calcium by precip. So the calcium never catches up.

 

[porpoiseaquatics]

I've moved the setpoints so let's see what happens. As soon as it kicks on, I'll check the bubble rate too. I've heard 1 bubble per second. Does that sound about right?

 

[reeferman]

thats a good general starting point.i always adjust mine through the set point and pretty much leave the bubble rate about 1 per second

 

[porpoiseaquatics]

reeferman;1065061 wrote: thats a good general starting point.i always adjust mine through the set point and pretty much leave the bubble rate about 1 per second

That's exactly what I did yesterday. My bubble rate somehow had increased to something like 10 per second. Now it's 1 per second with an "on" point of 6.5 and an "off" point of 6.8.

 

[grouper therapy]

Jeff the calcium reactor will not adjust the alkilinty level in the tank. To reduce the alkalinity one of two things will need to be done. Water changes with a balanced alk calcium ratio or the addition of calcium which will bring the alk down. To get the alk down I would shut down the ca reactor.It will continue to add alk to the tank and calcium in the correct ratios which in turn does nothing for the elevated alk level. There was a article on this subject RH Farley done to help with the 4 different scenarios I will try to find it. The best way to set up the reactor though will be to start with a balanced system which will be done as mentioned either water changes or dosing in you case perhaps turbo calcium .

 

[grouper therapy]

 

[porpoiseaquatics]

Thanks! I'm doing a water change today and shutting down the reactor for a little while. It's due for annual maintenance anyway.

 

[bcavalli]

Couldn't you shut down the reactor and just dose 3 days of 100ppm mag and then dose up to 440 calcium. Dependent on your Alk usage leave the reactor off until your Alk falls down to your target and continue to dose Calium based on your daily usage. Once it's balanced fire your reactor back up and you should be good. I have plenty of supplements if you need any.

 

[porpoiseaquatics]

Bcavalli;1065145 wrote: Couldn't you shut down the reactor and just dose 3 days of 100ppm mag and then dose up to 440 calcium. Dependent on your Alk usage leave the reactor off until your Alk falls down to your target and continue to dose Calium based on your daily usage. Once it's balanced fire your reactor back up and you should be good. I have plenty of supplements if you need any.

That would probably work as well.

 

[grouper therapy]

Bcavalli;1065145 wrote: Couldn't you shut down the reactor and just dose 3 days of 100ppm mag and then dose up to 440 calcium. Dependent on your Alk usage leave the reactor off until your Alk falls down to your target and continue to dose Calium based on your daily usage. Once it's balanced fire your reactor back up and you should be good. I have plenty of supplements if you need any.

Where have I heard that before?

 

[bcavalli]

grouper therapy;1065155 wrote: where have i heard that before?:d

:d

 

[porpoiseaquatics]

Update: I shut off the CaR yesterday (left it circulating internally but not dripping to the tank) and did a 10% (20 gallon) water change. Alk has already dropped 2 dKh in less than 24 hours. If it continues at that rate, I should be back where I want to be within the next 24 hours.