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Discussion Starter · #1 ·
hello, i have Red Ludwigia (Ludwigia repens)it grow like a weed but old growth gets black spots on it looks like crap.does anybody know what causes this or had the same problem and fixed it.its a 45 gallon high ei dose and pressure co2 in the green.thanks.
 

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I have this going on with mine, and from what I understand it's due to low nutrient levels, more specifically nitrogen and phosphorous.

Keep in mind I'm still new to all the chem with pants in a aquarium but I believe this is right,

and welcome to TPT.
 

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90% of plant problems are due to lack of good CO2 consistent with the light level being used, which is usually too high. (OK, maybe it is 60%, but it is still the major cause of plant growth problems.) Fertilizing can be done almost without thought, by just following an EI method, so you know you always have enough of all of the nutrients. But, getting the CO2 right can be a big puzzle for many people, and the percent that understand that you don't need very high light intensity, normally used with reef tanks, to grow plants isn't nearly as big as it should be. Always look at those two factors first and get them "right", before worrying about specific nutrients.
 

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Are you getting the black spots on new leaf or the older ones? Are you using micros also?
 

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Discussion Starter · #6 ·
Are you getting the black spots on new leaf or the older ones? Are you using micros also?
iam getting the spots on the old leafs,new growth is redish green very nice new growth. i think my problem is not enough phosphates i was dosing 1 cap of florish phosp,i ordered some KH2PO4 from green leaf i also noticed spot alage is starting.the co2 is at 4 bps through a external reactor and drop checker is green. my new light i got is 6 x18watt t5ho which is highlight but its a 29 inch high tank.iam going to adj my n&p when i get my dry phosphate.i dont know what one cap ful is equivalent to, but i am almost positive that it is not as much as 1/8 tsp. of dry fert.my other plants are growing like crazy, old groth on them are ok. are you having the same problem?yes iam using csm+b with seachem iron also.
 

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6-T5HO bulbs will give very high light intensity on a 29 inch high tank, unless they are located in three rows of 2 bulbs per row. That will make controlling algae a continuing difficult problem. Black spots on old leaves in a high light tank is usually BBA, which is difficult to eliminate without having the CO2 concentration as high as the fish can live with, along with very good water circulation in the tank, non-limiting dosages of all of the nutrients, and meticulous tank maintenance.
 

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Discussion Starter · #8 ·
6-T5HO bulbs will give very high light intensity on a 29 inch high tank, unless they are located in three rows of 2 bulbs per row. That will make controlling algae a continuing difficult problem. Black spots on old leaves in a high light tank is usually BBA, which is difficult to eliminate without having the CO2 concentration as high as the fish can live with, along with very good water circulation in the tank, non-limiting dosages of all of the nutrients, and meticulous tank maintenance.
yea i know that very high light ,once plants grow in i will cut it down .i inspected leaves today it is not a algae its pinholes starting .was reading deficiency seems it might be potassium ,i think .i know the lights are running the plants into over time ,but only have a slight problem with GSA.turned up co2 a little more i will see what happens.(K is very mobile and signs first appear in older leaves, this can turn uniform yellow before they die. Pinholes appear in them and slowly enlarge. The new leaves are reduced in size and leaf area)
 
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