Alkalinity Issue

[c4haskett]

I'm a little stumped. I am currently dosing 2,400ML kalkwasser in a 150G system nightly, and my Alk is consistently 6.7-6.8 dkh. I am trying to maintain 8 dkh, so i manually dose soda ash every night about 45ML worth to raise it up slowly in increments of .4 dkh. However, when I test again next day (same time) my number is back down to that 6.7 - 6.8 dkh range. I did this for about 5 days in a row, even upping my kalk dosing a couple times. The problem is, when I skip manually adding that soda ash in every night, my numbers will still stay the same in that 6.7 - 6.8 range. (You would expect it would drop even lower). I have confirmed that after dosing soda ash my numbers do hit that 7.2 - 7.3 mark about 30 minutes after dosing. I test with salifert, every evening around 6:00 P.M. My other numbers all fairly consistent are:

Alk- 6.7
CA- 415
MG-1420
N03- 2
P04- .04

 

[Randy Holmes-Farley Verified Community Expert]

Seems like you may just be offsetting demand, which includes organism consumption and precipitation onto sand/rock/pumps/heaters.

Demand rises substantially with alk, so keep it higher may require more every day. It's not just a correction.

Likewise, when it drops, the drops slows considerably as the levels get lower.

 

[c4haskett]

Seems like you may just be offsetting demand, which includes organism consumption and precipitation onto sand/rock/pumps/heaters.

Demand rises substantially with alk, so keep it higher may require more every day. It's not just a correction.

Likewise, when it drops, the drops slows considerably as the levels get lower.

Thank you, Randy. Which way would you go about this? I don't think adding anymore kalk would be helpful, so increase soda ash?

 

[Randy Holmes-Farley Verified Community Expert]

Thank you, Randy. Which way would you go about this? I don't think adding anymore kalk would be helpful, so increase soda ash?

High pH boosts demand. Using a lower pH alk supplement, such as bakign soda, instead of the soda ash, may allow higher alk, although that may not be an advantage.

In any case, adding more alk seems reasonable as long as you do not see things like sand hardening, indicating precipitation.

 

[Project1004]

How are you implementing your kalk dosing? Are you mixing it at full strength? 2400ml is little over half gallon and your system is 250G. I dose half gallon of kalk on 50Gal at full strength and still need to dose 2parts.

 

[c4haskett]

High pH boosts demand. Using a lower pH alk supplement, such as bakign soda, instead of the soda ash, may allow higher alk, although that may not be an advantage.

In any case, adding more alk seems reasonable as long as you do not see things like sand hardening, indicating precipitation.

Thanks again.

 

[c4haskett]

How are you implementing your kalk dosing? Are you mixing it at full strength? 2400ml is little over half gallon and your system is 250G. I dose half gallon of kalk on 50Gal at full strength and still need to dose 2parts.

I dose starting in the evening over a period of 14 hours of fully saturated Kalk using a hydros doser. I don't have many sticks, but it seems I'm still underestimating how much I need.

 

[wcharon]

How are you implementing your kalk dosing? Are you mixing it at full strength? 2400ml is little over half gallon and your system is 250G. I dose half gallon of kalk on 50Gal at full strength and still need to dose 2parts.

Can you share the full strength mix?

Thanks in advance...

 

[Randy Holmes-Farley Verified Community Expert]

Can you share the full strength mix?

Thanks in advance...

Full strength kalk is about 2 level teaspoons per gallon (~1.4 g/L). There's nothing wrong with adding excess solids and letting it settle out on the reservoir bottom.

 

[wcharon]

Full strength kalk is about 2 level teaspoons per gallon (~1.4 g/L). There's nothing wrong with adding excess solids and letting it settle out on the reservoir bottom.

Excellent. Thanks Master... Appreciated.