Now that i have my tank just about finished (lighting, plant/bio load) i need to start learning more about fertilizers. Right now im using flourish root tabs, and followed the directions. Some of my plants had started to turn yellow, so i did a Fe test, ( i know they're unreliable, but its better than nothing) And im reading zero. So i started dosing Flourish Iron last week. Before i started dosing Fe, i have noticed my Rotala losing its leaves, and my baby tears turning brown and dieing off. All in all i think my tank is doing pretty good for my first SERIOUS attempt at a planted tank. Help anyone, i dont know much about ferts at all! Tanks again everyone!!

some of the things you will need, CSM+B Plantex this has trace fertilizers.
Mono Potassium Phosphate (KH2po4)
Potassium Nitrate (kNO3)
Potassium Sulfate (K2SO4)

if your trace does not have enough iron in it you can use (Iron Chelate 10%)
I am still new to all of this but i can help you some. if you still need help PM me.

Are the 2x 20W lights meant to be for plants or to view the tank? I would change out those bulbs.

Anyway, to answer your question, the basic gist of plant growth works like this:
Light drives all growth. With more light comes the need for more CO2. With more CO2 comes the need for macro nutrients, or NPK (Nitrogen, Phosphate, Potassium). Some of these, mainly nitrogen and phosphate, can come from fish waste and fish food. However, if you have high enough light and you are giving the plants sufficient CO2, you will probably need to add NPK (emphasis on the Potassium, K). Think of these as plant food. Plants also require micronutrients, or trace fertilizer. These include iron, which you are already dosing, magnesium, calcium, and other things that I can't remember. Think of these as plant vitamins. You probably don't need to dose Fe alone. You could get away with dosing just a trace fertilizer, such as CSM+B, a dry fertilizer, or Flourish (regular Flourish). Be careful when dosing these not to overdose much, as they contain copper, which invertebrates are very sensitive to.

Your current amount of light is just on the cusp of low tech and high tech, so I guess you could call it mid tech. Since you are using DIY CO2, I recommend you keep up with it, as unstable CO2 could cause algae problems later. Use a bubble counter and a check valve to monitor the CO2 production in your bottle and to prevent siphon action. Keep up with your yeast mixtures, and change them out when you start to see the bubble count slow down. I would also recommend you consider running more than one bottle, starting them on staggered weeks. Also, you may want to start a bottle before the first one stops producing. Finally, since you are using a Penguin, I would recommend you remove the biowheel and keep the tank topped off to reduce surface agitation.

A popular method with many people on this forum is the EI method. EI, or estimated index, is designed to reduce the need for testing. This is good because many tests are completely inaccurate and useless (for example, iron. It is unlikely you had absolutely no iron in your water). The basic idea with EI is to ensure plants have enough of all nutrients, then dilute them at the end of the week with a large water change. This ensures that there isn't a ton of excess nutrients for algae to use.

Here are some places to start looking for dosing info:
http://rexgrigg.com/ferts.htm
http://rexgrigg.com/dosing.htm
https://www.plantedtank.net/forums/wa...-regimes_.html

Yes, i have two 20w 2800k Flora Glo lightbulbs i use for the morning and evening. During the day i keep them both on and a 65w 6500k pc. Is this adequate lighting? THANKs again for the help!

Have you thought about using a drop checker/CO2 indicator with a known 4 dKH solution to monitor your CO2 levels since you have a Penguin HOB 150gph w/Bio-Wheel and you're doing DIY CO2?

I'm using the following dosing regimen and it works really well.
http://www.barrreport.com/estimative...chy-folks.html

my penguin HOB has already been modified. Took out the biowheel and added some biomedia, and the tank is always filled to the top. Right now i have a red sea Co2 test kit and it seems pretty useless. I keep seeing the glass piece with some liquid in it, in many pictures. is that what your talking about??

Which Red Sea CO2 test kit do you have? They make two different ones.

I've had a Red Sea CO2 test kit that also came with an Iron test kit and both were useless as you said. It was called the Plant Care test kit: http://www.bigalsonline.ca/BigAlsCA/...antcareminilab

The other Red Sea CO2 kit is mentioned below.

Yes, some types of drop checker are glass and some are made of plastic.

Red Sea makes a CO2 indicator that you put inside the aquarium and put the known 4 dKH solution and indicator fluid in it. The indicator fluid is really the pH indicator solution that's used to measure from a pH of 6.0 to 7.6.The directions that come with it say to use aquarium water with the indicator fluid. That defeats the purpose of indicating the CO2 level. It invalidates the pH/KH/CO2 relationship. Using the known 4 dKH solution allows you to use the pH/KH/CO2 chart to determine the CO2 level in your aquarium. When it's green, you have around 30 ppm of CO2. When it's yellow, it has too much CO2 and when it's blue, it mean there is too little CO2. It's a neat little tool for checking the CO2 level just by looking at it because it's kept in the aquarium.

Here's some drop checkers/CO2 indicators.
Some of my tanks have these Red Sea ones: http://redseafish.com/Product.asp?di...D=64&proID=231 and http://www.bigalsonline.ca/StoreCata...Type=0&offset=
I have some made by Sera: http://seraessentials.com/product.cf...id=244&id=4320
Here's ADA's glass one: http://www.adana-usa.com/index.php?m...products_id=13
Here's some on ebay: http://search.ebay.com/search/search...ker&category0=