Ca Reactor - Alk rising, Ca + Mg dropping

[Fisherman Joe]

Hi all.

Been running my Ca reactor for about 6 months and it was stable at about 9.8.

I recently refurbished it as the media was turning to mush. So I cleaned it up, added new Ca and Mg chippings and since I cannot get the KH stable.

It tends to rise all the time.

I have the CO2 dripping through at about 1 bubble every 10 seconds and the drip in to the tank is set to about 1.5/2.0 drips a second.

ATM the parameters are:

dkh: 10.2
Ca: 380
Mg: 1280

What should I do now? Turn off the reactor, dose Ca and Mg then turn it back on?

Problem is, once it's on the dkh seems to move around too much.

A few weeks ago I turned the CO2 bubble down to one every 15 seconds. The dkh plummeted to 7dkh and I lost 4 heads on my Duncan's coral and one on my torch coral. Sad day. RIP.

I just want a proven was to keep the system stable. Any hints, tips and advice welcome.

 

[Randy Holmes-Farley]

Reduce the CO2 even more, if possible. In between 10 and 15 would sound like an appropriate value based on what you wrote. Alternatively, you could stay at 10 and increase the effluent water flow rate.

 

[Fisherman Joe]

I heard it's important to keep the flow quite high.

Whats easier to alter?

 

[Randy Holmes-Farley]

Depends on your setup. Both will work fine.

Not sure what you mean by keep the flow high. Most reactor flow rates are quite low in the scheme of things.

 

[Fisherman Joe]

So is it best to fix one and adjust the other?

Get the CO2 bubble to say 10 seconds and then adjust the flow to fine tune it?

ATM I'm lowering the bubble rate and increasing the flow to lower the dkh and Ca in parallel, then Spain my Mg up to the desired levels.

Is thy correct?

I heard that if the flow is too low in the reactor it can cause problems.

 

[Randy Holmes-Farley]

So is it best to fix one and adjust the other?

Get the CO2 bubble to say 10 seconds and then adjust the flow to fine tune it?

ATM I'm lowering the bubble rate and increasing the flow to lower the dkh and Ca in parallel, then Spain my Mg up to the desired levels.

Is thy correct?

I heard that if the flow is too low in the reactor it can cause problems.

I don't see why low flow would be a problem, but I've not really experimented with such scenarios. Chemically it isn't an issue.

Fixing one and adjusting the other is usually easier than changing two things at once.

 

[Fisherman Joe]

Is it best to turn off the Calcium reactor while correcting the imbalance or is it possible to do it with the reactor on?

I have lowered the bubble rate and increased to flow to help lower the dkh, at the same time i am gently upping my Mg from about 1280 to 1350. But my Ca has dropped to 370.

 

[Randy Holmes-Farley]

Either can work. Off will get you there faster, but then you need to restart the reactor and get a new optimal setting.

Turning it down will take longer, but once you arrive the reactor is set (or nearly so).

Id make a one time correction to the calcium as well. The reactor can't be used to raise it much because alkalinity would rise too much.

 

[Fisherman Joe]

On another note, i tested the pH of my effluent from the reactor, it came in at 6.7, i know most guides recommend 6.5 but i worry that will increase my dkh too much.

ATM, my Ca is 420, after i buffered it as you suggested. My Mg is still 1290 or so, im adding a lot, the max i can safely and its only going up 10-20 ppm at a time, it should go up more, but my dkh has now dropped and stabilised at around 8.6.

What would you do next?

 

[Fisherman Joe]

BTW, my bubble is down to about one every 15 seconds and my drip is quicker than one a second.

I dont want to alter anything so that my dkh starts creeping back up, but am i overlooking something that will effect the reactors performance in the long run?

 

[Randy Holmes-Farley]

I don't think I'd adjust anything at the moment. If the alk has stabillized at 8.6 and that is close to what you want, then all's fine.

Don't worry about the pH in the reactor. There is no magic number. It is just a guide to help you set things.

 

[Fisherman Joe]

HELP!! My dkh dropped 4.5!

Why and what should I do?

 

[Randy Holmes-Farley]

That seems unlikely. Corals and such cannot drop it that low in most cases.

Are you sure you measured correctly?

I recommend 7-11 dKH.

 

[Fisherman Joe]

I was dosing Mg and it wasn't rising at all. I worry it was a delay.

 

[Fisherman Joe]

It's a true result. Tested 3 times with fresh samples.

 

[Fisherman Joe]

What should I do?

 

[Randy Holmes-Farley]

I was dosing Mg and it wasn't rising at all. I worry it was a delay.

Are you adding a calculated amount?
With magnesium it takes a huge amount to make it rise since there is so much in seawater and even solid magnesium supplements are typically only 11% magnesium by weight.

 

[Randy Holmes-Farley]

What should I do?

Just double check your new salt water to make me happy (and to verify the kit) and if it really is that low, I'd boost it with baking soda dissolved in fresh water. Maybe 1-2 dKH per day for 2-3 days.

 

[Randy Holmes-Farley]

What magnesium additive did you add?

 

[Fisherman Joe]

Red Sea. I added 60g a day for 3 days. The Mg didn't move then it rocketed. I will get some dkh buffer and boost it back up. Then turn the reactor back on. Sound good? It's a 350L tank btw.