How do I automate Foz Down dosing via ATO??

[TimT]

I just had someone ask me how to automate Foz Down Dosing via ATO so I thought I would post the steps listed in my private response to them. Hopefully this will help other people to see how easy and inexpensive it really is.

Here's what I would do.
1. Remove the GFO reactor once media is exhausted.
2. Next day test Phosphate level.
3. Test the Phosphate level again the following day to get an idea of the amount of Phosphate produced by tank on a daily basis. If the readings between step 2 and 3 are the same then I would wait 5 days but divide the result by 5.
4. Measure how much water your ATO uses on a daily basis.
5. Calculate how many days your ATO reservoir of water will last.
6. Calculate how much Foz Down to add on a daily basis to remove the Phosphate calculated in step 3.
7. Multiply the amount calculated in step 6 by the # of days worth of water in the ATO reservoir.
8. Add the amount of Foz Down calculated in Step 7 to the ATO reservoir and then fill ATO reservoir with RO/DI water.
9. After ATO reservoir is empty measure the Phosphate level in tank and adjust dosage as necessary.

Here's an example:
100 gallon aquarium produces 0.01mg/l phosphate per day and has an ATO reservoir that holds 5 gallons of water. The ATO reservoir uses 1/2 gallon per day.

Step 3: = 0.01 mg/l

Step 4: = 1/2 gallon

Step 5: = 5 gallons / 0.5 gallons/day = 10 days

Step 6:
1 drop of Foz Down will remove 0.04mg/l Phosphate from 10 gallons. This can also be expressed as 0.04 * 10 = .4mg/l in 1 gallon.
The tank produces 0.01mg/l for 100 gallons which equals .01mg/l * 100 gallons = 1 mg/l in 1 gallon.
If we divide 1.0mg/l per gallon from tank production by 0.4mg/l per gallon removed by one drop of Foz Down we get 2.5 drops per day.
So the tank would need a daily addition of 2.5 drops to neutralize the Phosphate produced.

Step 7: 2.5 drops per day from step 6 * 10 days from step 5 = 25 drops.

Step 8: Add 25 drops of Foz Down to ATO reservoir and then fill with RO/DI water.


Conclusion to the example:
An 8 oz bottle of Foz Down contains about 4800 drops(240ml * 20 drops/ml). This would mean that the Phosphate in the tank could be neutralized for: 4800 drops per bottle / 2.5 drops per day = 1920 days per bottle or 5.26 years.

Every tank will be different in daily Phosphate production. This depends mainly on the amount of food going in. Some tanks may have bound up Phosphate in the rocks and sand that will need to be removed first.

This is why I say that Foz Down is a great way to control Phosphate.

Cheers,
Tim