Laith

What you should not do is mix KH2PO4 and any Fe trace mix in a bottle in order to dose them together. The concentrations in the bottle will be such that the Fe and PO4 will combine (FePO4) and precipitate out.

However, adding each separately to a tank shouldn't be a problem as they will very quickly become very diluted. Using autodosing I dose both every day but just to be on the safe side they are dosed a couple of hours apart. I probably wouldn't have any problem dosing them within minutes of each other or even at the same time at different spots in the tank...

Squawkbert

2 notes
- CaCO3 has limited solubility so you may want to pre mix it in a little hot water, then add it in w/ replacement water during a pwc.

K2HPO3 (dibasic potassium phosphate) is more readily soluble than the monobasic variety and it adds twice the K per unit. Drawbacks - may not be as readily available to everyone, pH is higher than for the monobasic. There is a "tribasic" out there, but it's even less common in labs etc., pH would be higher still and it's no more soluble than dibasic (if memory serves).

eklikewhoa

Thanks for clearing that up.

nos

Well let me see if i understand everything

I'm used to liquid solution, litters and grams so i will use this units and i will use Chuck's online calculator

I'm going to try EI in a 30 litter water tank (7.93 gallons) so will pick the 10-20 gallon example (off course i will reduce a little the fertilization, but thats a detail for now)

10- 20 Gallon Aquariums

+/- 1/8 tsp = 0.125 g of KN03 (N) 3x a week
+/- 1/32 tsp = 0.15 g KH2P04 (P) 3x a week
+/- 1/32 tsp (2ml) Trace Elements 3x a week
50% weekly water change

As i say i will make a 250 ml of KNO3 and 250 ml of KH2PO4 and i will fertilize 5ml 3x a week. So by my math:

KNO3
6.2 g for 250 ml = 0.51 ppm => 0.51 ppm * 5 = 2.55 ppm = 1/8 tsp of KNO3

KH2PO4
7.5 g for 250 ml = 0.7 ppm => 0.7 ppm * 5 = 3.5 ppm = 1/32 tsp of KH2PO4

Please let me know if this math is correct!

This is a simple example of what to do to convert dry ferts in solutions ferts

John N.

The goal is to have at least 5 ppms of Nitrate per dosage. So by increasing the KNO3 mixed in the 250 ml solution, we can get 1 ppm per 1 ml dosed.

KNO3
12 g for 250 ml. 5 ml of stock solution dosed is 5 ppm of N, thereby hitting the target goal.

KH2PO4
Calculations above look good. However, instead of using the full 5ml dosage, only 2-3 ml 3x a week is needed.

-John N.

nos

Tanks very much, i will try it

ocdiscus

Ok guys... I have a 160 gallon aquarium that is planted and I want to try EI dosing. I am completely new to the EI dosing scene and want to know what I should buy from Greg Watson's, and what would be a good dose amount and how often?

THx

hoppycalif

Assuming you have average tap water, you need KNO3 and KH2PO4. You also need a source of trace elements, which can be Greg Watson's CSM+B or it can be a commercial trace mix, such as Flourish. Your big tank will go through commercial trace mixes pretty fast, so CSM+B would be the best idea. Assuming you have about 300 watts of PC quality light with good reflectors, I would start by dosing 2 tsp KNO3 3X per week, 3/4 tsp KH2PO4 3X per week, and 1/2 - 3/4 tsp CSM+B (dosed dry) 3X per week. If you have much lower light than 300 watts, I would cut down to 2X or less per week. If your water has a low GH, or little or no Mg component of the GH I would dose Greg Watsons Barr GH builder too.

Laith

Laith

Sorry, I just realized I referenced this same thread... Not enough coffee that morning...

For a 160g you could start out with the dosing suggested for a 100-135 gallon tank. Watch the plants and adjust accordingly. Assuming 140g of water in your tank, that dosing will give you almost 10mg/l of NO3 per dose and just over 3mg/l of PO4 per dose. You could even start out with slightly lower PO4 dosing.