I have been dealing with GDA for quite some time and finally made some headway in the last few weeks.
The only solution Id found in the past was to reduce lighting intensity by raising my fixture a few inches and maintaining the photoperiod. This would usually reduce or get rid of the GDA temporarily, but I didnt like having to raise my light and lose the growth.
The 'wait 3 weeks and pray' method never worked for me and just felt silly. Especially when you do some research and realize that the species of algae that is often proposed as the source of GDA (Ankistrodesmus) does NOT have a spore stage. Also, i have examined my GDA under a microscope throughout all stages of its life in my tank and it looks nothing like Ankistrodesmus.
This is because it is the zoospore(asexual) stage.
I stated this years ago FYI.........
You can refer
It states quite clearly, it does have a spore stage(sexual and asexual). There's also somewhere around 100 species in the genus. The ID was made by a senior phycologist at UF, Dr Phlips. Dr Davis also confirmed. I have far less experience than they, it is possible they are incorrect, but I seriously doubt it.
You'd have to offer something far more concrete than this..... in other words to convince me.
Recently though, I'd read through the method of controlled imbalances thread on the 'other forum'. That thread mentions changing the Mg to Ca ratio (more Mg). Its a very interesting read, well worth the time. I would not take everything in there for gospel, but it really opened my eyes and convinced me to try a new approach.
Well, is this anything to do with balances or algae, vs simply adding more nutrients like Mg that might simply be limiting plants?
Refer to Liebig's law of limitation, basic reading that the PPS and MCI crowd seems very willing to suspend for their belief.
This does not imply that those 2 methods to do not work, just not for the reasons they claim them, which is an important point. We can and have tested many cases well outside their parameters without issues and have been unable to inoculate. Plenty of folks use EI and get GDA also, but.....many do not pay much attention to Mg in general.
It is very simple and straight forward to add more and see the plant response.
Algae will be secondary.
So i started adding Mg, but my tap water is pretty hard to begin with (gh of 12) and my R Walichii stunted on me. Based on some research, this seemed to indicate too much Mg so I have started doing my water changes with 1/4 tap and 3/4 distilled water for the past two weeks. I then add a small amount of Mg. My R Walichii no longer stunts and, much more exciting, i have gone two consecutive water changes without seeing even a hint of that ugly green curtain that i was so used to seeing within 3 days of a scraping
I have had tap water in Davis CA where the Mg is 52ppm, 5x higher than claimed by Edward(he claimed 10ppm as I recall).
I cut this by 1/2 with RO, so about 25ppm Mg.
It grows much better with good Mg.
HAS NOTHING TO DO WITH THE RATIO.
I think it's safe to say that many faster growing stem plants do better on a diet of higher Mg.
The contolled imbalances thread also states that a high level of phosphates contributes to GDA.
So why none of my tanks could ever be inoculated at 5ppm 3x a week of PO4 as KH2PO4? Ya know, this type of rubbish can and has been falsified, and yet folks still fall for it over and over. History repeats. Nothing new
is really learned this way.
I could also say the same thing about high levels of light. Nutrocentric algae correlatives, rather than plant horticulture, that's the root of the issue. These issues are almost always much more general and centered around poor plant care.
At what ppb/ppm range of PO4 does GDA become limited?
If you can answer that, then you begin to discuss this claim and know what range is required.
It is interesting to note that my tap water contains 1 ppm of phosphate. I was also adding even more phosphate with my standard EI dosing and my tank used to run between 1 to 2 ppm phosphate. At the same time that i started cutting my WCs with distilled water, I also cut phosphate from my EI dosing regiment. My tank now starts the week with about .25 ppm phosphate after my WC and becomes almost undetectable by the end of the week before the next WC.
Folks routinely dose 2-3ppm to prevent GSA, been doing it for 15 years on 50 or aquariums over that time. Many tanks chew through .8 to 1 ppm a week.
I dose 5ppm 3x a week on this tank:
A few years later, never any algae:
I have a dozen or more tank's like this.
i know that it is supposedly outdated thinking and frequently derided, but I do believe that high phosphate levels Contribute (not necessarily sole cause) to GDA. More clearly: I think that the MCI thread is right when it states that the RATIO of phosphate to nitrate is important.
I have gone from 50:1 or 1:1 N:P...........and very wide range indeedy.
I've not found any correlation.
This is something folks CAN and HAVE tested.
This is not about feelings or telling you what you wanna hear.
You must have a control reference to test and mastery over your methods. If not, then you cannot test the hypothesis.
Many have troubles with their methods........they are not good folks to do the test. It is only the folks who have mastery that can do this test.
Because you need a reference control.........
If I have a well run planted aquarium with high PO4, or any whacky ratio of N:P, and I do not induce algae(you can pick any species), and we can do this test 5-10X, and say on several aquariums.......no algae, no plant issues, no fish issues, not invert issues..........
It's fairly safe to suggest that those parameters in and of themselves are not dependent.
Which means they do not contribute.
You cannot have it both ways.
Tom will surely point that I am changing multiple variables simultaneously and, with no control, nothing is proved. I wont argue, but, if you're at the end of your rope with GDA I would recommend 1)reading through the Method of contolled imbalances thread in its entirety 2) changing your Mg to Ca ratio (more Mg) and 3) changing your Phospahte to Nitrate ratio (less Phosphate)
Hehe, is this your point? So you are offering hope an faith, not any real argument then?
I do not need to touch the multiple variable thing, the argument already had issues to start with. This MCI thing runs folks through the entire backwards roundabout way of PMDD, which is 16 years old. Add more of these other fert to limit PO4, then once you end up with GSA, then you can go back to normal.
This is not new, this is old.
if you do read the MCI thread, i would recommend skipping the 'protocol' that he recommends and just tinkering with your existing dosing regimen to change your ratios instead. That protocol seems a bit extreme and seems like it could throw your tank out of whack if not managed very carefully.
Why would a ratio matter versus an absolute concentration of the individual nutrient?
Do you even know anything about Liebig's Law of limitation?
It's considered a Law for a reason.
Ratios matter regarding fertilizer cost at larger scale ag situations. They matter when massive extremes that occur in soils, particularly where irrigation and high rates of evaporation. I find little agricultural evidence concerning ratios from Epstein and Bloom's text on mineral nutrition of higher plants, 2nd edition that might apply to aquatic weeds/plants.
Even less if we look at algae and macrophytes together in Florida lakes.
There's simply no/very little correlation.
Sorry for the novel, but just wanted to share the results I've had. Hope this is helpful.
Nothing wrong with that, but folks have had success with the wait and let it go method, others with CO2, others with Mg adjustment upward.
Is is correlation only?
Most do not care and just want the algae gone, so some of these suggestions really play to the desperate aquarist, not that the methods actually fix things because of what the author states.
I think if folks focus on the plant needs and good care, then algae is RARELY ever an issue. This philosophy is pervasive and should be the focus, not some round about way to subtle fert ratios etc as some cure for the desperate. I'm not alone, the research above suggest this, Amano states this, CAU also states this.
So something like Mg seems like a likely candidate, but has little to do with any ratio. Either way, better to test and see what things are step wise, rather than adding everything and the kitchen sink and hoping. Then you can isolate and learn more... not just about algae, but about plants.
This seems much more reasonable and supportable.