Sword leaves have holes and crypt falling apart

[cplawrence]

I have a 75 gallon tank with 130W of PC light and no CO2. It is pretty well stocked with fish, so I do not dose NO3 very frequently, but try to keep it close to 20 ppm. Phosphate is kept between 1 and 2.5 (best I can tell with the test kit....) I have been dosing potassium 10 ppm when I do a weekly water change and 5 ppm every other day. Iron (CSM+B) is added once a week for about 0.01 ppm. Sword plants have been getting DIY root tabs once per week. Things have been going fairly well so far, but I have a couple of amazon sword plants that have small holes in a couple of the leaves and the remaining leaves are somewhat translucent. I know holes are associated with a potassium deficiency, but is it still reasonable to point the finger there given that I am now dosing about 25 ppm a week?
Just in the last couple of days, two crypts (bronze wendtii I am guessing--labeled simply as cryptocoryne at LFS) have started purging leaves as well. It is not melting in that the leaves are dissolving, they are simply coming off of the plant. They were not moved recently and had grown quite substantially from purchase several months ago.
Any guesses as to what should be done?
Thanks,
Chris

 

[fish_4_all]

Well, I thought that fert tabs were supposed to last up to 2 months, even do it yourself. It could be an overdose of something to the roots. If all your fertilizers are there then it could be the problem, too much of something getting to the roots. Tell us what you put in your root tabs and maybe we can help there.

As for the crypts, I don't know personally but have heard large swings in parameters can cause them to fall off or melt.

The biggest problem I can see right off is the lack of CO2. At 2.3 watts per gallon, you really need it to help the plants process nutrients and aid in growth.

 

[cplawrence]

The root tabs are:
1 part plantex
1 part MgSO4
1 part KNO3
2 parts K2SO4
5 parts clay

 

[fish_4_all]

The only thing I see from what I have read is that you might not have enough PO4 in the water column. Also, it is very odd that you have to use so many of them. Are they smaller than the normal plant tabs or about the same size? A little much on the K2SO4 but i have not read anything about that being a "bad thing". I am also curious about your actual levels of NO3 mostly due to a possible bad test kit. If you know how, test it to make sure it is accurate.

Also, CSM+B, I would dose it 3 times a week. I dose mine 3 times a week at .2-.3 ppm iron and my swords love it without root tabs. I get a few holes in my Red Melon sword but only in older leaves so I know mine are happy but need root tabs to really meet their uptake needs.

Last and again, add CO2. I think your plants are at a bypass where they are trying to grow fast and not being able to grow as fast as they should because they have very little CO2 for photosynthesis. Most will tell you that you will see healthier and happier plants with CO2 added even in lower light tanks.

Hopefully someone else will either verify what I am trying to get across or stear you in the right direction. I only know what I read here and sometimes it gets really confusing. I really think it could be nothing more than a real lack of CSM+B due to the very low ppm you dose each week.

One other thing since I am thinking about it. Remember that each part is based by weight, not volume.