i have seen many method, most popular one is letting the gda attach to the glass and wait for 3-4 weeks, i have tried it several times and it never worked for me. another method was reducing the light might slow it down but this also slow down plant growth, i had GDA growing in low light and reducing the light doesn't do anything, it made things worse, most plant started to suffer.
when i first setup my tank with ADA soil, started dosing EI, this is when i have seen the biggest outbreak of GDA, i know aqua soil release tons of ammonia during cycle process, but am not sure how much Phosphate it releases in the water. just keep in mind am not bashing EI here, i also tried my own Fertilizer, which actually add more ammonium in the water, GDA was still there, most plants were growing very fast, so was the GDA, actually it was growing faster than the Plants. i have tried reducing the light, GDA grew at fast rate while plant started to struggle.
have you ever notice that GDA can start in the lowest part of the tank and no gda on the top glass, where light is couple inches away from it, how come there is more GDA on the lower part, where light hits in less amount? so you guys still think too much light cause this algae, i dont fully agree, next time look at your tank and see where you see the most algae and you will get the answer.
MCI method known as method of controlled imbalanced, i came across this recently and never heard of it before, even though it was there for long time. before i came to find out about this method, i was dosing 3ppm of Ca during water changes, this is total amount of Calcium in the water and about 0.3ppm of Mg everyday, plant grew very fast and i was also dosing my own recipe know as Happi's ultimate fertilizer, there was no sign of GDA or any other algae, in my recipe there is a lot of NH4 and Fe, i think that extra Fe might been reacting with some of PO4, i was dosing 1ppm of PO4 3x week, i cannot confirm if the reaction was eliminating most of the Fe and PO4 from the water. MCI claim if Ca is higher than Mg and you have too much PO4 you will get GDA, later MCI also mentioned that they are not saying ratio should be Ca 1 and Mg 4, they said Mg is more important than Ca and ratio isnt much important long as Ca isn't very high. i can confirm this because as you can see in the next paragraph, but i still have doubt about it sometime.
when i use to dose EI, i kept all the parameter the same except Mg, i use to dose 3ppm Ca and 15ppm of Mg during water changes, during that time, stem plant use to go wild and tank looked very clean and healthy, no sign of any algae, GDA not even once. maybe plants were using everything i was throwing at them.
i also hear increasing the co2 would help with GDA, actually i have seen it make no difference to GDA, sometime there was more GDA when co2 was very high.
summarize:
GDA can grow in both low or high light, low or high co2. low nutrients or High nutrients, keep in mind i always dosed the same amount of PO4 when using EI or my recipe, GDA was present in both cases and it sometime did not occur in both cases. i think Mg has something to do with it, i always found Mg to help reduce the GDA.
i will soon find out if PO4 and Ca/Mg ratio is the cause of GDA as mentioned by the MCI method. am on my first week of only adding KNO3 and no PO4, have done three 50% water changes to remove PO4. MCI claim i should get green spot algae once po4 hits 0, so far it has been a week and no GSA algae to be found on the glass, GDA is still growing, but i must agree that it is much less than before. am still waiting for the GSA to appear and we will see if it will ever appear, we cannot disagree with MCI on this because this is mentioned everywhere.
story about newly setup tank:
ADA 60 H was setup 3-4 weeks ago, this is run by odyseaa 54 watts, first week of dosing there was no algae, GDA started to show up on the next week, it did not start closer to the light, it was on the lower glass first. i was dosing very low PO4 0.5ppm 3x week. now this makes me believe if GDA is caused by PO4 then Aqua soil must be releasing plenty of PO4, but at a same time i believe it cant be true. i guess after i get GSA in my tank we will know for sure, lets see if MCI claim is true or not. i would also line to mention when i was using PMDD without PO4, there was no sign of GDA or any other alage, but some plant did not grow properly, light was intense and co2 was kept same, in same setup when i switched to EI to make the plant grow better, green dust algae did appear, no offense to EI here.
EDIT: some people here are confusing GDA and GSA, they are two different algae people, GSA (green spot algae) which is hard to come off and GDA (green dust alage) which comes of very easily.
NEW UPDATE
i tested both of the tanks for phosphate that have GDA, API test kits read 0ppm, am not sure if phosphate kits are accurate, but for right now algae is still there, but it haven't spread much. this puts MCI at question, if MCI owner was still around i would ask him this question, but i guess he is not. but its too early too tell, i haven't dose phosphate for 2 weeks now, lets see what happen next. i have left the algae alone and see how far it could spread.
when i first setup my tank with ADA soil, started dosing EI, this is when i have seen the biggest outbreak of GDA, i know aqua soil release tons of ammonia during cycle process, but am not sure how much Phosphate it releases in the water. just keep in mind am not bashing EI here, i also tried my own Fertilizer, which actually add more ammonium in the water, GDA was still there, most plants were growing very fast, so was the GDA, actually it was growing faster than the Plants. i have tried reducing the light, GDA grew at fast rate while plant started to struggle.
have you ever notice that GDA can start in the lowest part of the tank and no gda on the top glass, where light is couple inches away from it, how come there is more GDA on the lower part, where light hits in less amount? so you guys still think too much light cause this algae, i dont fully agree, next time look at your tank and see where you see the most algae and you will get the answer.
MCI method known as method of controlled imbalanced, i came across this recently and never heard of it before, even though it was there for long time. before i came to find out about this method, i was dosing 3ppm of Ca during water changes, this is total amount of Calcium in the water and about 0.3ppm of Mg everyday, plant grew very fast and i was also dosing my own recipe know as Happi's ultimate fertilizer, there was no sign of GDA or any other algae, in my recipe there is a lot of NH4 and Fe, i think that extra Fe might been reacting with some of PO4, i was dosing 1ppm of PO4 3x week, i cannot confirm if the reaction was eliminating most of the Fe and PO4 from the water. MCI claim if Ca is higher than Mg and you have too much PO4 you will get GDA, later MCI also mentioned that they are not saying ratio should be Ca 1 and Mg 4, they said Mg is more important than Ca and ratio isnt much important long as Ca isn't very high. i can confirm this because as you can see in the next paragraph, but i still have doubt about it sometime.
when i use to dose EI, i kept all the parameter the same except Mg, i use to dose 3ppm Ca and 15ppm of Mg during water changes, during that time, stem plant use to go wild and tank looked very clean and healthy, no sign of any algae, GDA not even once. maybe plants were using everything i was throwing at them.
i also hear increasing the co2 would help with GDA, actually i have seen it make no difference to GDA, sometime there was more GDA when co2 was very high.
summarize:
GDA can grow in both low or high light, low or high co2. low nutrients or High nutrients, keep in mind i always dosed the same amount of PO4 when using EI or my recipe, GDA was present in both cases and it sometime did not occur in both cases. i think Mg has something to do with it, i always found Mg to help reduce the GDA.
i will soon find out if PO4 and Ca/Mg ratio is the cause of GDA as mentioned by the MCI method. am on my first week of only adding KNO3 and no PO4, have done three 50% water changes to remove PO4. MCI claim i should get green spot algae once po4 hits 0, so far it has been a week and no GSA algae to be found on the glass, GDA is still growing, but i must agree that it is much less than before. am still waiting for the GSA to appear and we will see if it will ever appear, we cannot disagree with MCI on this because this is mentioned everywhere.
story about newly setup tank:
ADA 60 H was setup 3-4 weeks ago, this is run by odyseaa 54 watts, first week of dosing there was no algae, GDA started to show up on the next week, it did not start closer to the light, it was on the lower glass first. i was dosing very low PO4 0.5ppm 3x week. now this makes me believe if GDA is caused by PO4 then Aqua soil must be releasing plenty of PO4, but at a same time i believe it cant be true. i guess after i get GSA in my tank we will know for sure, lets see if MCI claim is true or not. i would also line to mention when i was using PMDD without PO4, there was no sign of GDA or any other alage, but some plant did not grow properly, light was intense and co2 was kept same, in same setup when i switched to EI to make the plant grow better, green dust algae did appear, no offense to EI here.
EDIT: some people here are confusing GDA and GSA, they are two different algae people, GSA (green spot algae) which is hard to come off and GDA (green dust alage) which comes of very easily.
NEW UPDATE
i tested both of the tanks for phosphate that have GDA, API test kits read 0ppm, am not sure if phosphate kits are accurate, but for right now algae is still there, but it haven't spread much. this puts MCI at question, if MCI owner was still around i would ask him this question, but i guess he is not. but its too early too tell, i haven't dose phosphate for 2 weeks now, lets see what happen next. i have left the algae alone and see how far it could spread.