I am in an older moo baan in Chiang Mai and have this problem on a recurring basis, and its bloody awful when they get out of hand (like tonight). I am trying to get the lids and vents to the system sealed against mozzies, but its not yet been effective.

I have one 1000 litre black plastic septic tank ("tang-kee") buried in the garden but the locking rim of the lid has now come loose. Should I use silicone or cement to fix it to the concrete collar of the tank?

Also, there needs to be some chemical product that kills the larvae but does not stop the septic process - I can sometimes get blue sachets from a garden supply shop that works (sort-of) but there has to be something better. The usual septic tank powders and tabs aren't effective. Ouch, just got bit by another *&^! mozzie!!!!!!

TheScribe.

Hi Scribe: I once read that mossie larvae need surface tension to 'breath" and that if you eliminate that with soap or is it detergent or somesuch? they will drown. Similarly a thin layer of oil would work.a little veggie oil of some sort would be okay in your tank?

Re sealing the tank...maybe impractical since it is vented I assume . Try putting mossie screen over the whole shabang and of course the vent pipe if it exists.

What about covering the 'Lid" with a layer of dirt on top of the mesh???

good luck

The locking rings are always breaking, I have replaced two in two years, looks like they were broken when fitted. You can buy new locking rings, failing that spread a meter of the same blue gauze sheet that goes into the soffits (roof overhang) then put the whole broken locking ring back, some plants in pots on top of the plastic lid to keep it flying off and you will never see the little critters, worked for us before I got around to replacing the lid assembly.