# Confused about dry fert dosing...



## slidez (Jan 4, 2008)

I've been dosing with Seachem's line of fertilizers for a couple of months now and I am getting good growth but not exactly what I was looking for so I decided to opt for dry ferts to save cash.

Now I have read a bunch of threads and I cannot find small enough measuring spoons (pinch/smidgen) to dose directly to the tank so I decided to make a liquid solution. 

Previously I've just been dosing the full recommended ppm level's from the fertilator all in one day, and then resetting the tank with a 50% water change at the end of the week. But the more I read about the EI method, I'll need to split up those doses to 3x a week. Now here's where it gets tricky..

I've done all the math to make a liquid solution to dose almost all the different chemicals but I got stumped on phosphates. The fertilator suggests 0.5 - 2.0ppm of phosphates, and up until now I have been dosing that amount in one dose for the whole week until my water change. But when I checked on the fertilator 1/32 tsp of KH2PO4 for 20gals (as suggested by EI Method) would be aprox 1.5ppm of phosphates. Then if I had to dose that 3x a week that would be 4.5ppm of phosphates when the recommended level is 2.0 max!

Can someone help me clarify what the phosphate levels should be? Every other thing like nitrate dosage seem about right when I convert them, and they all seem to be building up to the recommended ppm levels with 3 doses for a whole week....


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## xPat (Jan 31, 2008)

Hi slidez, I was confused by this when I first starting dry dosing as well. But one thing I believe your forgetting about is the fact that when your dosing ferts aren't staying in the water column but being used by the plants.

So if you dose 1.5ppm of phosphate 3x a week as per EI method you won't have 4.5ppm of phosphate in your water at the end of the week. And the 50% water change is meant to remove what the plants don't consume. Or so I under stand, I'm sure people who know more than me will correct me if I'm wrong.


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## hoppycalif (Apr 7, 2005)

If you replace 50% of the water every week, the highest concentration you can get dosing EI is twice the total weekly dosage of each fertilizer. And, if the plants use any of the fertilizers, obviously the maximum concentration will be lower. Tom Barr's experiments before he proposed the EI method showed that you can go even higher than the two times the weekly total dose without any noticeable effect on the fish or plants. In fact many of use dose as much as twice the EI amounts of phosphates to try to avoid or control green spot algae, and haven't seen a problem from doing so.


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## slidez (Jan 4, 2008)

Does this mean that I should overshoot the recommended values rather than staying below the maximum? For example on nitrates the fertilator says 10-20ppm, I've been dosing around 10-15ppm and estimating about 5ppm from the fish. Should I just shoot for the full 20ppm instead and try to stay over the maximum recommended but not too much to ensure the plants are getting all they need?


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## hoppycalif (Apr 7, 2005)

There are two schools of thought on fertilizing - one is to always have non-limiting concentrations of every needed nutrient. The other is to attempt to provide just what the plants need, no more. The first is an easier goal - just use the EI fertilizing method. The second requires more attention to the tank, more measuring and adjusting of dosages. People are successful using both approaches.


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## Left C (Jun 14, 2005)

The fertilator has some flaws with calculating some of Seachem's products. It shows that there is iron in some products that do not contain any iron at all. These are F. Nitrogen, F. Phosphorus and F. Potassium.

The http://www.fishfriend.com/fertfriend.html calculator is better for use with Seachem's products.

Here's a Seachem Dosing Calculator if you need it. http://www.aquaticplantcentral.com/...ng/45119-seachem-dosing-calculator-chart.html


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