I have a 135 gallon mixed reef, 6 years old and stable. I would like to keep my alk around 8.5-9. I dose kalk as the only Alk/CA addition. I do monthly 20% water change with reef crystals. I find that after a water change my alk is around 8.3-8.5, but over the course of 3 weeks to a month my alk drops to under 8. In the past I've tried increasing the kalk dose to accommodate, but find that my calcium goes well over 500. I re-read Holmes-Farley article 'When Do Calcium and Alkalinity Demand Not Exactly Balance?' and it seems that the recommendation IS to add more kalk to compensate. So my question is, at what point do I worry that my calcium is too high and starts to have some negative affect on other parameters? Is there an alk additive that is best used in conjunction with kalk, if I decide to go that route? Tangent to this, I also occasionally use calcium carbonate as a flocculant after blowing off reef or stirred up gravel (10ml in the published formula using RO) maybe once a month. Does this have any affect on parameters? Other pertinent facts I can add is that I dose vodka to keep my nitrate around 20, and use rowaphos to keep my phosphate around .10.
Alk dropping while using Kalkwasser
- Thread starter Key Largo
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If you trust your calcium test, you can just add food grade sodium bicarb to increase Alk. Are you doing waterchanges? The calcium carbonate flucculant has little/no detectable effect on parameters, when used as described.
Randy Holmes-Farley
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My Tank Thread
I think there’s a misunderstanding somewhere. My recommendation would not involve kalk if you believe that calcium is too high for some reason.
That said 500 ppm calcium is not a problem. :)
Biff0rz
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How often are you adding kalk to your stirrer? I have to add it weekly to keep the alk up. Subsequently, I have to clean out the stirrer monthly lol. To add more alk if the kalk isn't sufficient without calcium, I would dose Sodium carbonate (soda ash) -- adds a lot of alk (potent) and raises ph without adding calcium. win-win.
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Key Largo
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"Table 1 shows what can happen when the dosing is inadequate. Alkalinity drops fairly rapidly. After one day, many aquarists might conclude that they need additional alkalinity, when in reality, they need more of both calcium and alkalinity to stabilize the system".
This is where my misunderstanding may have arisen. Since I use Kalk, that how i would add both. I use 500 CA only because that it the upper limit of current tests that I have. When/where does excessive CA become an issue? In that event which is the best Alk only additive to use in conjunction with Kalk?
In answer to answer another members question, I use a 6 gallon reservoir of kalk, just about weekly (the top 5.5 gallons anyway). I max out potency when filling (by conductivity) but potency diminishes somewhat over the week. I let the kalk settle before restarting doser, and I have a DIY gizmo that only draws from the surface.
This is where my misunderstanding may have arisen. Since I use Kalk, that how i would add both. I use 500 CA only because that it the upper limit of current tests that I have. When/where does excessive CA become an issue? In that event which is the best Alk only additive to use in conjunction with Kalk?
In answer to answer another members question, I use a 6 gallon reservoir of kalk, just about weekly (the top 5.5 gallons anyway). I max out potency when filling (by conductivity) but potency diminishes somewhat over the week. I let the kalk settle before restarting doser, and I have a DIY gizmo that only draws from the surface.
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