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vbsaltydog
03/12/2012, 01:32 AM
I am thinking of writing myself a program that I can feed in my Ca, Dkh, and Mg levels every week and it will tell me the proper daily doses of 3 part to use in order to hit my target levels (whether increase or decrease) based on my tank's consumption history.

There are simple calculators that tell you how much supplement to use to raise your levels to taget x but are there any calculators in existence that will analyze your readings over time, calculate the average consumption (over the past few weeks) and output the necessary doses to lower, maintain, or raise the levels?

If there are no existing calculators, are there any dosing pumps that can do these calculations?

Randy Holmes-Farley
03/12/2012, 07:16 AM
I've not seen a calculator like that.

That said, one wouldn't use the doses in the past aside from the current dose to make such a calculation. :)

drparker
03/12/2012, 07:26 AM
vbsaltydog I can see how useful that would be. I would think you'd need to know water volume very close to reality. It would somehow need to take into account how this would be affected by water changes.

vbsaltydog
03/12/2012, 07:37 AM
vbsaltydog I can see how useful that would be. I would think you'd need to know water volume very close to reality. It would somehow need to take into account how this would be affected by water changes.

Yes, I thought of the water change issue. Here are my initial thoughts:

Every weekend for at least 4 weeks (sample size reasons), record Ca, Dkh, Mg

Every week, the program calculates the consumption as:

logic:
(starting level + dose level) - ending level = consumption

examples:
(450ppm + 50ppm) - 450 = 50ppm maintain
(450ppm + 50ppm) - 425 = -75ppm loss
(450ppm + 50ppm) - 500 = +50ppm gain

use the average consumption over the last 4 weeks, if that many are present in the db, to avoid single data set anomalies.

Obviously, this is for a time period where the tank inhabitants dont change drastically. If you add 15 sps colonies mid week then you calculate consumption on the current week only.

Randy Holmes-Farley
03/12/2012, 07:54 AM
Personally, I think dosing changes are best done by trial and error, not calculation.

You can actually only accurately predict what amounts it takes to make a one time boost. You cannot predict what the demand will be as you change doses because demand for calcium and alkalinity and magnesium rise as the alkalinity and pH rise. Depending on the magnesium level you start with, demand for calcium and alkalinity may rise or fall as you adjust magnesium as well.

So in the end, trial and error is the best way, IMO. :)

vbsaltydog
03/12/2012, 08:05 AM
Personally, I think dosing changes are best done by trial and error, not calculation.

You can actually only accurately predict what amounts it takes to make a one time boost. You cannot predict what the demand will be as you change doses because demand for calcium and alkalinity and magnesium rise as the alkalinity and pH rise. Depending on the magnesium level you start with, demand for calcium and alkalinity may rise or fall as you adjust magnesium as well.

So in the end, trial and error is the best way, IMO. :)

Error being the operative word that I am trying to avoid as much as possible. You are right that the chemistry is dynamic and relative so a change in X = a change in Y. All I am really trying to accomplish is to use empirical evidence to track patterns of consumption so I can establish a baseline dosage to keep the parameters as close to my targets as possible. I understand that it will be impossible to "dial it in" to the ppm. Thanks :)

Rploaded
03/13/2012, 06:01 AM
I made one in excel. I put in my readings and it shows me change from my desired level. I then have an action column. I manually fill that in with the dose I selected. I fill it in daily usually. My tank stays very consistent......

vbsaltydog
03/13/2012, 01:46 PM
Glad to hear that it works.