Co2, Fertilization, Algae and more updated 10/10

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AC Members
Dec 19, 2011

How do I use these fertilizers and the Estimative Index?

Fertilizing via EI is simple. Every other day dose the prescribed macros elements, and on the off days add in the trace/micro elements. Perform a 50% waterchange at the end of the week. By following one of the commonly used dosing programs below for your specific tank size you can ensure your plants are getting what the need throughout the week.


100-125 Gallons
1 1/2 tsp KNO3 3x a week
1/2 tsp KH2PO4 3x a week
1/2 tsp K2SO4 3x a week
1/2 tsp (30ml) traces 3x a week

i have 100 g tank and i want to use above dosing regime..

i have one difficulty.. i dont have tsp.. i have gram digital weight.. so when above says 1 1/2 tsp or 1/2 tsp, how much gram that would be ?


AC Members
Sep 17, 2014
Nashotah Wisconsin
Real Name
Bob Escher

co2 is often the most limiting factor in planted tanks. some plants need it and can speed up plant growth by 10 folds.

there are 3 common ways to add carbon to your planted tank. pressurized co2 diy co2 or excel which is a liquid form of carbon. excel can melt some plants and the gas is a better option if you can afford it.

for a pressurized system there will be more up front costs but cheaper in the long run.
must have: co2 tank, regulator, needle valve and a way to break up the co2
optional: Solenoid, check valve, ph controller, drop checker

tips on pressurized co2 set up.

co2 buy as big as you can fit. i have a 20 and a 10 pounder. the bigger ones only cost a few more to refill and last longer.
regulator there are many different ones out there. rex grigg makes top of the line one and will help you with every step. many people also pick up Milwaukee regulators on ebay or other sites.
needle valve lowers the psi so your out putting 1-2 bubbles per section. each take is different so it might take time to dial in what yours needs.
solenoid isnt a must but lets you save co2 by shutting it off and on at night or hooked up to a ph controller.
check valve keeps water from backing up for what ever reason and flooding the house.
ph controller with a ph controller you can set it for the ph you want. once it gets to that level it will shut the co2 off.
drop checker this is a simple yet great way to measure co2 in you tank visually. it changes color as the co2 levels raise or lowers. one important part is to make sure you have 4kdh liquid to fill it with.

Drop Checkers/CO2 Indicators-Why and How

the problem i often see is how to break up the co2 into the water. there are lots of options.... glass diffuser input or output of a filter, reactor, ladders, power heads, wood air stones and more. all these have their own place some work better then others. ill break them down with pros and cons in how i see them. again my experience might be different the others.

Glass diffusers breaks up the co2 into small micro bubbles great to put under the out put of the filter to help blow them around. the con is it can clog up over time.
input/output filters one of my more favorite ways to break up co2. i put the tube into the input or to the out put of a canister filter or hob. this breaks it down really well and spread though out the tank. the con in the input it can air lock a filter some claim it even breaks down a canister. con for the output doesnt always break up the co2 as well as input
reactor is a great diy type of way to break co2 up. i feel the best ones are working with the output of a canister powering it. there are also intake reactors but take up tank space.
powerheads are another one of my favorite ways to break up co2. it does take up some take space but it breaks the co2 very good and pushes it though out the tank.
wood airstones while these work they dont work very well

tips on DIY co2
its very easy but takes time. you need soda bottle/juice bottle sugar yeast tubing.

mix 2 cups sugar and 1/2 tsp of yeast with warm water 2/3 the way high. it should last 2 weeks or so depending on temp. i would also highly recommend adding a 2nd smaller bubble counter. this will keep the mixture out of your tank.

Co2 Thread

i say its only good up to 20 gals tanks though people do use multiple bottles.

a couple places to get regulators that i have seen here.

Best Aquarium Regulator

I realize this this is old but I am new here so here goes I have a 29 gal planted tank with flurite, and eco complete sand and very small gravel ( how ever they come as substrate. I have 5 amazon swords that are small haven't grown their tall single shoot offs , I have used excel, and flourish to no great success and in the last three week also a co2 tank (small) with a bubble counter and a ceramic differ user ( which works good) but the plant leaves slowly are losing color ( one by one on a plant and I trim them off)
Ten hours of white and three of blue. I turn off the co2 when the light is not on.
suggestions on the plants and what to watch for with the shrimp ( although they seem to be ok.
i have excellent filtration ( 2 cannister filters, 2 sponge filters and a DIY floating bed filter which I started a week ago, aeration and water movement is excellent as well, slow with the plants moving slowly and the fish love them and the shrimp 6 so far are all over the place as well

thanks for any replies


Global Moderator
Staff member
Jan 11, 2013
West Falls NY
Real Name
bescher, how long has this 29g been setup? Amazon swords are heavy root-feeders. You may need some root tabs. 5 of these swords in a 29 can overtake the tank. I had one fill a 10g and moved it to my 55. The root system it formed in my 10 was impressive. Why so much filtration on this 29? I have better luck with plants with very little water movement. Too much surface agitation will negate most of your CO2. FWIW, I used to add a gluteral product for CO2 (like Excel). I don't add any form of CO2 now. I let the fish/critters do that.


Mar 29, 2005
Question for you. If I buy the fluval 20g co2 system, could I buy a bigger co2 yank for it so that I'm not changing it so much?
Personally I would look towards a regular or paintball CO2 tank and suitable equipment from there.

the new CO2 cartridges get expensive and dont last long, you also have to manually open and close the CO2 daily or have it run 24/7

give it a go if you can find a suitable deal, but seriously think about a refillable source of gas and a decent regulator... a solenoid valve would be a benefit too.


AC Members
Aug 1, 2007
Kansas City, MO, USA
Real Name
Clearly things have changed the past 8 years that I haven't had a planted set up. So, if you get the gist, I used to have the Hagen Nutrafin CO2 Natural Plant System. They have Upped the price on those now and the newer model, Fluval Mini Pressurized 20g-CO2 Kit - 0.7 ounces is completely different. I never learned much about pressurised CO2 systems, so do you have a good place that I could learn a few things about them, what they require, and all the bells and whistles?


Mar 29, 2005
I dont think it has changed too much in the past decade, but people became more tired of yeast based CO2, so pressurized became more popular.

There are a number of links earlier in this topic which may prove useful. I am on my phone and dont know of anything of real value from the top of my head, maybe I will look tomorrow.

but if you have specific questions, start a thread of your own and ask away :)
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AC Members
May 4, 2002
North Ga, USA
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