Here is a dosing guideline from Tom Barr's website. (Actually I took down the link cause I'm not sure if we can post links to other forums. So you will have to google that, sorry!)
Also be sure to check out our site's sticky in the fertilizer section of the forum. Here is the sticky.
Its a good read, especially the first post. It has pretty much the dosing of EI listed there too plus some other handy info to check out. I'm sure this is what he is going by since he created EI, the Estimative Index.
I would assume you can post a link to the site, I cannot due to conflict if interest, even as a power seller and subscriber..........
Didn't use to be that way.
Anyhoo, I've only had one 75 gal tank in the last decade, when I was in Florida.
EI has many different versions that I did not write, most are fairly good and within reason.
Ferts are not difficult, no matter what anyone likes to say about them......CO2 is and light a fair amount less if you go on the low side.
Some get all rigid about dosing, this is NOT the type of folks you wanna talk to. Rather, realize that EI is simply a method to provide non limiting ferts regardless of light and CO2......you obviously in 99% of cases will need less, so if you care about dosing less for some reason, you simply add a tiny bit less progressively each 2-3 weeks and till you hit a spot where negatuive growth or appearnace starts, then bump back up to the last highest dosing.
Or.....not. It will not hurt fish, shrimp or any plants.
Some folks use low light and do water changes once a month like this above.
No issues, I do this on 2 tanks myself.
Other tanks with high loading, maybe 2x a week, most tanks for most folks, weekly is good.
50% makes the math easier for many, but you can do 80% if you wish, you'll have less error and build up.
Some do 1/3rd of the tank, etc........and accept a little bit more error.
If the CO2/light is well balanced, you should have a wide range of fert dosing........remember that part about not listening to the people who claim rigid things about dosing? They got issues with the light/CO2 is all cases.
Adding ADA AS etc to the sediment will provide even more neglect and wiggle room in dosing also.
So I think the light, CO2 sediment sources should always be discussed in the context of the dosing.