I'll confess that I skipped ahead when I saw some scientist/lab tech bashing. I've been in the hobby over 50 years, but I'm a fishkeeper that uses plants for water purification. Oh I really like my planted tank with surreal naturalization. However, most of my tanks leverage fast growing floating plants to make for better water for the fish. I only use enough ferts to keep the plants growing well. With that in mind, EI just doesn't make sense to me. I've tried different brands but right now I'm trying Select Aquatics Rapid Grow
plant fertilizer. But instead of the dosing method Greg Sage suggests, I'm adding a little after each water change. I'm not far enough along to swear by it yet, but it sure seems cost effective. (I too like the "all-in-one" ferts, but don't much like the cost...especially since they're mostly water.)
Different strokes for different hobbyists...what works best is what works best for you!
I have been wanting to try Greg Sage's mix actually! I am also a fishkeeper first who enjoys the beauty of plants as well as how much they help me with my water. I totally agree with what you said about EI being too much for that kind of tank.
One thing we really haven't touched much on is how much fish load affects the amount of fertilizer needed. I generally overstock and over filter my tanks. Because they are over stocked I feed a lot of food per water volume which puts a lot of phosphates and nitrates in the water everyday. I also remineralize my RO water with seachem equilibrium which is loaded with potassium. So my NPK's are already decently high before I dose anything, at least for a low CO2 tank. I think that could be another reason why an AIO might work for me but not work for someone @Greggz
Knowing Greg Sage doesn't do CO2 and also runs heavily stocked tanks and autofeeders, I bet his fert would be perfect for me. I have been wanting to try it for a while now so hearing that it works well for you gives me a bit more motivation. Does anyone else use his ferts?
Originally Posted by Sam the Slayer
I just meant the ph of the water in the aquarium. EDTA will start to degrade above a ph of 6 where as dtpa will hold until about 7.5. So when they say you’ll get x amount fe per dose which would be false for most people which will also have an effect on the rest of the ferts.
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I actually really hadn't considered that. You are certainly right, dtpa would be a better choice. Kudos!
I don't think it degrades but I get your point. EDTA has four carboxyl groups each of which loose a hydrogen at a different pH. The pka of EDTA's four carboxyl groups are 2, 2.7, 6.2, and 10.3. So even at the pH of 6 its already a 2- which I would think is enough to chelate ferric iron. When they do the chelation they do it at a pH above 10 so they have the 4-, but once ionically bound it should be relatively stable above pH 3.
I found this paper "Effect of pH, light, and temperature on Fe–EDTA chelation and Fe hydrolysis in seawater (Sunda et al, 2003)" which suggests in salt water ferric-EDTA begins to significantly dissociate at 7.7. Of course the sodium will help with the hydrolysis, but i wasn't able to find a freshwater reference. I'm very curious about this! @Sam the Slayer
if you have any references about how much ferric EDTA dissociates above 6.3 I would love to read them!
It is amazing how much I can learn from other hobbyists!
Originally Posted by Bunsen Honeydew
You quite literally said " I also admire the hobby because the technical expertise and knowledge required to set up a balanced ecosystem makes every aquarist a scientist in a way.". I was simply disagreeing with this. This is not to denigrate those in this hobby, just acknowledging that "experimenting" in our tanks, is not the same as running a real experiment. It's kind of in the same babe that the plural of anecdotes is not data.
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I meant only that the aquarist is a little bit of a scientist at heart. I never said experimenting in the tank was the same as running a real controlled experiment. Obviously I agree they are not the same which is why I said seachem was backed by the best science, because they actually did the controlled studies. I think this whole thread really is evidence that the planted aquarist is at least dabbling in science.