I have a very tiny nursery. One section is irrigated by a drip line that runs down a gravel bed, which happens to be part of our septic system. I guess I've been lucky as I've used it for 5 years with no problems. Now I'm getting lots of clogged drips and I find a white tissue-like slime sometimes.
I read that algae needs sunlight and this is likely bacterial slime, and that I should use chlorine. I don't have an injection system and will have to rig something up. I'm pleading for suggestions on how to fix this.
Would something like Zerotol work as well?
Not knowing how your system is set up let me guess at a solution. First of all you will have to get a chemical in the line to kill the growth. If it is small you might be able to dissconnect from the water line and just pour something into the line by use of a funnel and gravity. If you can connect a regular female hose connection to the line a simple "hose-on" proportioner can be used. I think they are a 1:16 ratio type proportioner and cost under $20. Once you can get something into the line you have to decide what to use to kill off the growth. In order from weakest to strongest.....
(lemon juice/vinegar/chlorine/Lime-A-Way/Zerotol/sulphuric acid)
If it is not a huge/complicated system it might be easier to throw it out and start with new.....
Zerotol might remove some but if it's as bad as I envision your going to probably need something more aggressive. I guess it really depends on how many drippers were talking about and how easy it is to pull all the drippers away from the plants. We use a product called Strip-it. It can be ran through the system or you can soak the drippers in it. It's not safe on plants so removing the drippers from the plants is required.
First I would install flush valves on the ends of your drip lines, These valves are open when the water pressure is under 2 lbs. When the pressure increases the valve closes. Install your drip lines so they will drain towards the flush valve. Next you will probably have to install a chemical proportioner AKA fertilizer injector and constantly inject a chemical to break the biofilm on the inside of the line. The product that works the best is Oxcide from Chem Fresh. http://www.chemfresh.com/
Even the best drip system needs regular maintance of the drippers. Do you have a filter on the water coming into the line? If not you need one and it needs to be check regularly. That will help eleminate the sand and other particulates that often plug drippers. If the drippers are plugged with hard water deposits you will need to try to soak them to get them clean. Putting in a flush valve and using it often will also help. Sometimes the cost of starting over new is less than the cost of fiddling with old parts, especially if the plants are at risk.
I have come across this before I am quite sure what you are seeing is calcium build up.. It is either coming from your water source or perhaps the fertilizer you are using in your water... run some vinegar through all the drippers, that should clear it up and then make sure you try to keep the calcium levels under 100o ppm or it will happen again.. good luck..
Thanks for the suggestions--they have helped a lot. We have real acidic water, so it's not likely calcuim. I've had slime (bacterial?) in other lines, but I've been able to flush that out by hand. It's the mechanics of cleaning out the drip line that had me stumped. Also my unwillingness to put anything environmentally harsh into the line, which drains into the gravel bed, which drains into the ditch.
I understand that flush valves would help this from happening in the future. They won't work in this location. I may need to add more drip lines in the future, and I could set it up with flush valves at that time, but I have to live with it like this for now.
I decided to get a kiddie pool and coil the line up into it where I could flush/soak the line and drippers. I was going to use bleach and water, afterwards pouring the solution out onto our brick walkway, where it might kill some of the mold that likes to grow there. Do you have to worry about soaking the line with bleach--I know from doing laundry that bleach will eat elastic when you soak with it.
Thanks again for all of your input, it made a big difference for me.