Advice on automated dosing of various products wanted

Hi Gilles,

Maybe I can help you a little bit on the second question: My tank is heavily planted 600 liters and 0,5 Watts per liter of light. It uses around 5 ppm of KNO3 and 0,5 ppm of KH2PO4 per day.

regards,
dutchy

 

Dosing EI for NO3 and PO4 would be the best you can do in my opinion. At least you're sure you don't lack nutrients.

50%WC is a no way for you? If no, you could try decrease the dosing by 30% once things are ok

Your PO4 stock solution is too light, you'll need too much liquid to add the needed PO4. 0.1ppm PO4 is really low, I target above 1ppm, EI even 4x this

 

The most KNO3 can be dissolved in 500 ml of water is 425 grams. KH2PO4 is 75 grams.

Regards,
dutchy

 

Chucks calculator gives you the solubility. Also, you can use google for example: "CaCl2 solubility"... will give you a wikii page with all info

Usually solubility is given for 20°C
You have to dilute the total grams of KNO3 in a small quantity of hot water. Once diluted, you top it to the 500ml mark. That's the definition of solubility and the base of ppm calculations. Not add powder directly to 500ml or you end up with more than 500ml volume and less ppm/ml

You can try less WC volume and lower dosing by 30% and see how it runs for you. Also, if you have low light, you can reduce dosing even more. By the way, a 500L tank will have usually around 350-370L (30% less or more, depends on tanks). But yes, still large volumes to deal with

 

Not sure if this helps. But..

NO3 daily uptake for non-limiting EI is about 4ppm with 100% uptake for heavily planted tanks. My daily dose is about 3.9ppm. Wet's calculator http://wet.biggiantnerds.com/ei/con_v_time.pl might help you decide if a lower dose with your water changes would work for you, but adding a daily dose closer to 4ppm would not harm fish and would give you something closer to the EI recommended dose .

PO4 uptake at 100% is around 0.6ppm a day. Again people around here keep water around 2ppm with NO3 levels around 10ppm and up. Keep some distance between PO4 and NO3, about 1: 5 - a non-limiting dose is the goal, not so much the ratios.

Plant mix is harder for me to say. I think you might save some money if you start using CSM+B. But, to finding the non-limiting amounts that work with your tank it is easier on the plants to start heavy and reduce your levels every two weeks until you find your "sweet spot". I did find this calculator http://www.fishfriend.com/fertfriend.html that would suggest your a little light on the levels of iron. Even PMDD suggests dosing 0.1ppm of iron daily.

You do not mention any Ca or Mg levels, but if they are low you need to find a fix for dosing those weekly.

On a side note - KNO3 can be added to your plant mix without causing any precipitates or add it to the KH2PO4 and add the Excel to the plant mix, to give you back two of your containers.