Iliveinazoo wrote: I think that the gist of it is that if you have accelerated growth then you have accelerated waste due to plants shading out others quicker and causing leaves to die off, if you prune almost daily then maybe you can cut down on the waste produced.
Okay now that make sense. I thought there was some "NEW" found chemical that fast plants were expelling that was harmful to fish. Ever see the movie, "The Happening". (hehe)
Iliveinazoo wrote: I had assumed that you were dosing EI whereby the strategy is to flood the tank so that no one nutrient gets to a level where plants would begin to show defficiencies, if you can create a balance in your set-up then great but surely you would have to spend oodles of money on test kits as the rate of uptake of the various nutrients would change regularly in your CO2 enriched system?
I am actually doing a synthesis of the Estimate Index (EI) method as well as the Perpetual Preservation System (PPS), whereby I do 50% water changes, BUT also test the water to hit target parts-per-million ranges. In the EI method, you are able to dose up to twice the amount of the target nutrients because the plants will consume some of that, then the majority of the excess nutrients will be siphoned off during a WC. No testing is really required once you get a ballpark idea of how much to dose.
In the PPS method, testing is done quite rigorously whereby you dose just enough nutrients to keep the plants healthy, which is a lot less than the EI method. However, because you constantly keep the nutrient dosing in check, it is said that water changes can be as infrequent as once every X years! I don't subscribe to this philosophy of aquarium care taking.
SOOOOOO...
I took what I liked about both methods and created my own. I dose as close to the target rate as possible and check that by testing. (e.g. nitrogen at 7 ppm, phosphates at 1.5 ppm, etc) and then do a large weekly water change. I test twice a week, once after a WC, and once during the middle of the week to give me a ball park idea of just how much to dose to hit those targets. That's not too often now, is it? The rate of uptake is for the most part pretty consistent, at least it is with my tanks, so I don't get a whole lot of variance.
I can't really adhere to the EI method because I have some really sensitive plants in my tanks, whereby if the nitrates are too high, (above 10ppm), and phosphates too low (below 1.5 ppm), the plants become stunted.
http://www.aquaticplantcentral.com/foru ... t&spec=Red I love my plants
almost as much as I love my fish
Nick wrote:Certainly enough nitrates are bad for fish - what I was trying to say is that if it's nitrates alone(like if you have nitrates in your tap water) it takes way way more to do harm than if the nitrates accumulate in the tank along with other indetectable waste products.
Okay, gotcha. I just always assumed that nitrates in of themselves were harmful. I don't live in an area that has any detectable nitrates in the tap water, so I never knew that such water existed. Sounds pretty bad if you ask me, but you get what you get I suppose. I always associated high nitrates as bad, period. But I do hear what you are saying.
Just out of curiosity, what are these other "undetectable waste products" that we as hobbyists can't test for, but maybe a lab could?
Nick wrote:Wow, this is complete and total crap based on a red herring fallacy. Rainwater does not significantly effect the chemistry of large bodies of water because there is not enough of it. Small bodies of water are sitting directly on top of a bed of minerals in the form of soils and rocks; tiny, narrow creeks flow quickly, water moving over mineral sources quickly, while 90% of the rainwater flowing into one has seeped through mineral filled soil on the way. This is the case for almost all rainfall - you can't call rainwater "ro/di" water. If you wish to compare the two, you would have to first dig up a big shovel of local dirt, pack it into a pipe, and slowly let the ro/di drain through before the comparison.
Also, PH crash happens ALL THE TIME. Working in a LFS, people with large predatory fish, where they tended to overfeed and change far too little water, came in with PH plummeting below detectable levels regularly, usually accompanied by nitrates off the charts. This "old tank syndrome" was obviously the product of acidification and nitrate build up from way too much bioload relative to the level of water changes.
YIKES!!!! That does sound dreadful. Not only are the fish drowning in their own crap, but then you get a pH crash on top of that. Well I suspected that line of thinking to be a bunch of BS. But since I've never experienced a pH crash before, nor have I ever heard of any first hand experience from anyone else having suffered from it, I just assumed it was a myth like the website states. Thanks for chiming in with your experience.