Tips for alk stability in high demand system?

[mahi03]

I have a 110g high-demand system. I was dosing close to 300ml of liquid soda ash daily before switching to a calcium reactor. However, I've been having trouble maintaining alk "stability" since making the switch, with daily swings from 8 to 8.7, and back. I've read that others may see their intra-day swings up to 1dkh and their corals are fine, but mine have not responded well - have had several acros RTN and a few gonis have closed up. While the coral issues may be attributable to something else, the timing of their unhappiness to these alk swings might suggest the swings are the culprit. The CARX is currently running 24/7. My PH fluctuates in a ~0.4 range daily (I already run a large CO2 scrubber on a recirculating system).

What are some techniques you've done to help minimize these swings? I'm thinking of maybe turning off the CO2 solenoid at night for a couple hours, and increasing the flow rate during the day. Maybe I can limit my 24/7 kalk drip to only at night to boost PH, and keep alk from dropping as much while the carx is off.

Anyone else have any tricks?

 

[mcarroll]

I have a 110g high-demand system. I was dosing close to 300ml of liquid soda ash daily before switching to a calcium reactor. However, I've been having trouble maintaining alk "stability" since making the switch, with daily swings from 8 to 8.7, and back. I've read that others may see their intra-day swings up to 1dkh and their corals are fine, but mine have not responded well - have had several acros RTN and a few gonis have closed up. While the coral issues may be attributable to something else, the timing of their unhappiness to these alk swings might suggest the swings are the culprit. The CARX is currently running 24/7. My PH fluctuates in a ~0.4 range daily (I already run a large CO2 scrubber on a recirculating system).

What are some techniques you've done to help minimize these swings? I'm thinking of maybe turning off the CO2 solenoid at night for a couple hours, and increasing the flow rate during the day. Maybe I can limit my 24/7 kalk drip to only at night to boost PH, and keep alk from dropping as much while the carx is off.

Anyone else have any tricks?

The crucial information missing is what your'e tank's nutrient situation is.

pH swings can be difficult for corals to manage if they are struggling for nutrients.

That struggle can happen under low concentration levels (ie ppm) as well as low flow conditions....flow is interlocked with nutrient delivery to corals.

The main way coral tanks become victims of their own success is by corals limiting flow in the tank by their growth (it is their nature).....so it's possible that it's time to upgrade your tank's flow. Maybe adding an extra powerhead or upgrading to more substantial powerheads.....just ideas. Rearranging the flow can help sometimes.

Your reef is a a CO2 scrubber, and using an external one is probably not vey productive – you're likely fighting against household CO2 levels, not against tank chemistry or poor aeration. A stable pH and stable system is more important than some specific pH number.

Do you monitor CO2 levels in room with the reef tank or in the house? That would also be more interesting data. CO2 monitors are cheap online. It'll let you know if just opening the door or running a fan in the room will make a difference....or if it will take a more significant change, maybe to the house's HVAC system.

 

[mahi03]

I have a 110g high-demand system. I was dosing close to 300ml of liquid soda ash daily before switching to a calcium reactor. However, I've been having trouble maintaining alk "stability" since making the switch, with daily swings from 8 to 8.7, and back. I've read that others may see their intra-day swings up to 1dkh and their corals are fine, but mine have not responded well - have had several acros RTN and a few gonis have closed up. While the coral issues may be attributable to something else, the timing of their unhappiness to these alk swings might suggest the swings are the culprit. The CARX is currently running 24/7. My PH fluctuates in a ~0.4 range daily (I already run a large CO2 scrubber on a recirculating system).

What are some techniques you've done to help minimize these swings? I'm thinking of maybe turning off the CO2 solenoid at night for a couple hours, and increasing the flow rate during the day. Maybe I can limit my 24/7 kalk drip to only at night to boost PH, and keep alk from dropping as much while the carx is off.

Anyone else have any tricks?

The crucial information missing is what your'e tank's nutrient situation is.

pH swings can be difficult for corals to manage if they are struggling for nutrients.

That struggle can happen under low concentration levels (ie ppm) as well as low flow conditions....flow is interlocked with nutrient delivery to corals.

The main wait coral tanks become victims of their own success is by corals limiting flow in the tank by their growth (it is their nature).....so it's possible that it's time to upgrade your tank's flow. Maybe adding an extra powerhead or upgrading to more substantial powerheads.....just ideas. Rearranging the flow can help sometimes.

Your reef is a a CO2 scrubber, and using an external one is probably not vey productive – you're likely fighting against household CO2 levels, not against tank chemistry or poor aeration. A stable pH and stable system is more important than some specific pH number.

Do you monitor CO2 levels in room with the reef tank or in the house? That would also be more interesting data. CO2 monitors are cheap online. It'll let you know if just opening the door or running a fan in the room will make a difference....or if it will take a more significant change, maybe to the house's HVAC system.

Appreciate the response!

NO3: 10 and PO4: 0.08

I do dose nitrates daily. CO2 in the home is high, I can tell you that without a monitor, but I do not know that levels of course: Windows are cracked when temperatures allow, which is about 75% of the year. The home does not have an hvac system (San Francisco) so I’m limited in what can or can’t be done to increase natural O2 in the home.

 

[mcarroll]

Appreciate the response!

NO3: 10 and PO4: 0.08

I do dose nitrates daily. CO2 in the home is high, I can tell you that without a monitor, but I do not know that levels of course: Windows are cracked when temperatures allow, which is about 75% of the year. The home does not have an hvac system (San Francisco) so I’m limited in what can or can’t be done to increase natural O2 in the home.

Older homes tend to leak enough air that CO2 buildup is much less of a problem.

If it's a new home you may have a real concern....supplemental ventilation is recommended for many common circumstances, like having a vented appliance (eg over, gas water heater, etc.)

IMO you may as well pony up for a CO2 meter....you will be surprised by the readings even though you've already got an idea of things. CO2 (or maybe house air in general) doesn't move like you'd think....or at least like I would think.

If you don't have HVAC (and relatively mild weather), then it actually a little easier to remedy....some folks crack a window just enough for the skimmer's air line to reach outside, but there are lots of other ways to get fresh air into a house or a room.

Nutrient levels seem fine, but you mentioned that's only due to dosing nitrate. What's going on to keep nitrates going toward zero? What is your filtration and cleaning system like?

 

[maroun.c]

If possible and airhose from skimmer to outside could help.+1 on the Co2 meter it was an eye opener for me. Back to the alk issue, an hourly alk monitoring for 1 day might show you the times where u need less dosing and u can run the reactor accordingly. The smaller volume on a high demand tank as u say sometimes also doesnt help.having enough water volume as buffer for swings.
Some people are also dosing all their daily alk (2part dosing) at light up in the morning which does contribute to a heavy alknspike in the morning and a drop over the day and night... and these systems are reportedly doing well.
Check Bolus method.
I wouldn't worry much about a 0.5 swing up and down during the day especially with the error range of our testing kits and equipment.