Okay it's been a while since I have posted on here... about 8 or 9 months ago I upgrade my aquarium with t5 lights and a pressurized co2 system and began fertilizing. I found so many differing opinions about the "way" to do things that I became confused and sort of jumped in.

Things are going great, but I think some of the plants should be much more full than they are and I'm having somewhat of a problem with algae. If anyone has some advice on the balance of co2/light/ferts with recommendations on specific products I would appreicate it!

75 Gallon
Ultra Sun t5 HO 6,500 K (has been left off)
Ocean sun t5 HO 10,000 K
Pressurized CO2


Lately I have only been leaving on the Ocean sun light, with the ultra sun off. The light is on for 8 hours per day.

Dosing powdered fertilizers every other day:
K2SO4 .5 tsp
KNO3 .5 tsp
KH2P04 .25 tsp
Plantex CSM+B .25 tsp

I'm not totally sure what type of algae I have. It may be 2 kinds. I try to rub it off of the leaves frequently, but it is impossible to get it all. Some is kind of thick and furry, and the kind on the amazon swords seems to be more of just a film.

pics
Tank:
Aquarium Gallery - photo_3_2

Algae on Amazon sword:
Aquarium Gallery - photo20

Algae on moneywort:
Aquarium Gallery - photo20

So, I'm guessing I probably need more fertilizers, based on some of the plants not really seeming to reach their full potential and the increase of algae. I'd like to have a better idea of what specific combination I can adjust. If you have any tips please let me know!! Thanks so much

Eric

idk if its just me but that seems like an overdose of ferts. could this cause excess algae growth?
also, how frequently do you change your water and how much of it do you change? I have to do a 50% water change on my tank every week to keep algae down and fert buildup down

I would try stopping the KH2P04 and just doseing twice a week with the same amounts and see how it goes. What is your bubbles per minute on the CO2?

Also what is your KNO3 reading

thanks to those of you for getting back so quickly! here are the responses to your questions...

- as far as the overdose - i came up with that amount from green leaf aquariums, where i purchased the powered ferts... i thought... but as i mentioned there were so many opinions on the subject matter when i set everything up that i just sort of dove in. i was just peeking on the website and i couldn't immediately find the dosing guide i thought i referenced.

- water change : i try to do 50% every week. sometimes I get busy and it is biweekly. When this occurs, i try to first siphon 50% of the water without vacuuming the gravel and replace. I then several hours later, or the next day... do another 50% this time vacuuming the gravel.

for my filter... i am not as good about this, but i maybe once every other month or 3 mos open up my filter and dump out the water in there, rinse all the parts and pieces in aquarium water and replace.

archer - why do you recommend ceasing the kh2po4? when you refer to the other fertilizers, do you mean using the same amount of dose, but just reducing that amount to 2x week?

I just counted the co2 and I had 66 bpm from my Milwaukee ma957 regulator. I have the co2 dispersing from a GLA atomic diffuser. Just above the diffuser if have a reef fan mounted to blow a current from the area around the tank. There seem to be an even amount of tiny bubbles floating in the water all over the tank as a result of that.

as far as my KNO3 reading, i have no means of measuring specific amounts of anything in my tank. the only kit i have for testing levels is ph, ammonia, nitrite and nitrate - which i stopped using after i my tank became established. is there a testing kit you would recommend for assessing fert levels?

Thanks again all!!

KNO3 is nitrate and yes continue to dose the same amounts but only twice a week, kh2po4 is phosphate and you get that from most of the foods you use so you might be high on that and that will cause algea. I would raise the BPM's up to about 300 per minute slowly as in over several days and keep an eye on things as you do this and run all your lights again. I was running about 600 per min on my 120 thru a reactor so I had almost totaly dissolved my CO2 into the water ie no bubbles and I didnt have any real algea problems.

it sounds to me that you followed the guide for the dosing wrong. Its easy to get wrong when you are adding ferts dry because the recipe given on the site is for if you mix the ferts with water and add it as drops.

i have a 55 gal and for 4 drops/gal which is the max recommended dose i add a little less than 1/3 of a tsp per day of dry powder ferts (I have the pre mixed bag containing 1 part K2SO4 1 part KNO3 1 part MgSO4 tsp and 1 part CSM+B). you should be just fine adding about 1/2 a tsp total per day (1/8 tsp of each fert). this should be plenty for a 75 gal.

as for your CO2, 68 bpm is pretty low for a tank your size. I run about 180 bpm on my 55 gal to keep it at about 25 ppm of CO2. you should try and either bump up your CO2 or turning down your light to decrease algae growth. if you want to see good growth on your plants increase CO2, if you dont care about growth decrease light.

hope this helps!

EDIT: after looking at different ingredients I think it might be a good idea to lay off the ferts with phosphorus in them all together, they really increases algae growth.