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Final Puzzle Peice. ...

Behold

Member
Joined
6 Aug 2008
Messages
218
Location
Basingstoke. Hants
Ok Ferts. I know im going to need them from what i have read as i have pure sand. I use API tabs at the moment but wanted to know what i should be using. searches just give me loads of others issues not help on choosing the right stuff.

should you monitor what deficencies you have or just provide whats needed??? What is good to use.

Thanks
 
OK so i need to buy 4 dry powders. but for a 500l tank im struggling to work out how many grams i should buy.......

Also Nitrate.... my water has about 40ppm in it as standard would this mean no need to dose?

Thanks
 
Well, that's like trying to figure out how much food you need to buy at the supermarket. Buy a half kilo of each and see what your consumption rate is. If dosed per standard EI the 125 USG tank tank would consume about 25 grams of KNO3 per week or 100 grams per month. It would use probably a 25 grams KH2PO4 per month and a little less than 25 grams of the Trace mix per month. This is not medication. It's food so you will have to feed your tank for the rest of your life. If you buy a lot of food that just mean you won't have to buy as much next month.

As regards your tap water I would question how you determined that your tap has 40ppm and whether that value is reliable. It may very well be accurate, in which case you would simply substitute K2SO4 instead of KN03 but I always doubt the values of the tap water report. Adding more nitrate than you need is never a problem but having less that you think is always disastrous. I personally would dose per the baseline numbers and only slowly withdraw the KNO3 in logical steps, such as a 25% reduction every three weeks, and let the plants prove to you what your tap water has.

Cheers,
 
So what PPM should i be aiming for on 1.5wpg light on each item?
 
Instead of aiming for some magical ppm value just dose per the standard values. You will get yourself into trouble if you focus on ppm, especially if you try to measure ppm. Neither EI nor PMDD are about micromanaging ppm. One of the reasons is that two tanks with the same ppm and even with the same wpg can have vastly different performances as a direct result of different filtration/flow/distribution, different CO2 levels different bioloads and so forth. The teaspoon/gram dosing provides baseline numbers which guarantee minimum ppm values. Adjustments to the dosing are made based on the tanks performance. If nutrient related algae or deficiency symptoms appear then dosing is adjusted upwards. If growth rates are too fast adjustments are made downwards. But the adjustments are more easily made by simple variation of the gram/teaspoon changes instead of being hypnotized by magic ppm values and only encourage people to test needlessly.

Of course, one can also easily assume that a 1.5 wpg is low enough energy and that the tap water content is high enough in macronutrients to justify a lower dosing scheme. If that's the case then just do something simple and logical like starting off with half the dosing values instead of the full values. For example, if you check the EI dosing article it states that the reference 20 USG tank gets the the following baseline dosing 3X per week => [3/16 teaspoon KNO3] + [1/16 teaspoon KH2PO4] + [½ teaspoon MgSO4]. If you wanted to start with "½ EI" therefore just start out with the alternative 3X per week => [3/32 teaspoon KNO3] + [1/32 teaspoon KH2PO4] + [1/4 teaspoon MgSO4].

That way you don't have to worry about the mathematics of ppm and the drudgery of trying to take into account what the tap has. This makes life much simpler.

Cheers,
 
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