Need fertilizing help - so confused!

[Kilgore]

I really don't know how I managed to make it through chemistry in order to get my biology degree, so please bear with me here. I will soon have two planted tanks and I am really confused on how to dose my fertilizers (all Seachem products currently but when these run out I intend to spend a lot less at Greg Watson's site). Anyway, these are the recommended dosages according to Seachem for my 25-gallon, but they are apparently designed for low-light setups. How much should I increase them considering I have 2.7 wpg compact fluorescent lighting? I need to know how much, how many times per week, if possible. I realize this is just to start with and I will have to adjust later according to results, of course.

25-gallon – Seachem recommended dosage:

Flourish – 2 ml (2 threads of cap) 1-2 times per week
Nitrogen – about 1.5 ml (1.5 threads of cap) twice a week
Potassium – 4 ml (4 threads of cap) 2-3 times per week
Phosphorous – 3 ml (3 threads of cap) 1-2 per week
Iron – ½ capful as needed (once a week?)
Excel – on water change day (more than 40%), 2.5 capfuls, then ½ capful every other day

And what about my 46-gallon that will have only 1.3 wpg? I want to add some lighting but money is limited right now.

I downloaded Chuck's Planted Aquarium Calculator but I am confused by one thing - is the targeted amount at the bottom the amount one wants to shoot for overall (as in, not to exceed this amount), or the amount one should aim to add each time? I guess I find it confusing because it tells me how much adding X will affect my levels, but not how much I should add. And once I've added it, then how do I know that the next time I add that amount it won't be too much? Aack! Does this make any sense? I intend to do weekly water changes of 50%.

Any help will be greatly appreciated, by me and my plants.

 

[bman]

I would start by using the recommended dosages by Seachem. The plants will tell you if they are missing something, and you can adjust as necessary. Eventually you will find the correct dosage for your tank.

Keep in mind that that the dosages will need to be changed according to the amount of plants you have as well.

I started with the recommended dosages for my 20 gallon medium light, medium planted tank, and have held pretty close to it over six months now, with almost no problems.

Make sure you have a test kit, especially for Phosphorous since you will be dosing that, plus I think the flourish has it in it as well.

Weekly 50% pwc is great to "reset" you fert levels in the tank until you get a good idea of what to add.

 

[7Enigma]

I think you'll find the Flourish dosage much to low for your tank. I was dosing slightly more than recommended (3 times per week 1-2ml) in my 20gallon with 65w CF lighting, and am just now recovering from a MASSIVE iron deficiency. It's good to know you have the iron as a separate additive, but you don't want to be limited by other traces as well if you just add Flourish in normal amounts.

Greg's CSM+B has made a major improvement in my plants in just a little over a week of use. CSM+B is ~7% iron while I believe Flourish is around 1%.

I would start with a double dose of Flourish for your tank, preferably double the "feedings" rather than double the amount each time (so dose 4 times a week 1-2ml) and start from there.

As soon as you see signs of iron deficiency then I'd do a single dose per week of the iron additive. Just don't wait too long as I did because while the plants are bouncing back, it has hampered their growth and allowed some algae to grow on the leaves.

 

[Purrbox]

If you look at the bottles for Flourish closely, you'll notice that there is a formula that allows you to determine how much you are dosing. Use this instead of the recommended dosing to determine how much you need to reach your targets. You want to aim for 10-20ppm Nitrate, 1ppm Phosphate, and 10-20ppm Potassium. Since there isn't a test kit that's affordable for Potassium just keep an eye out for Potassium deficiency to determine if you need to increase your dosing. Flourish Comprehensive needs to be treated similar to Potassium. If you start seeing Micro deficiencies, up your dosing slightly. At first you'll do a lot of testing on for NO3 and PO4, but after awhile you'll get a feel for how much they're using and will be able to dose without testing very often.

 

[ringfinger]

http://www.leon-huang.com/doser/