almost one month of build time has passed and i finally moved the wall in the tank for watering it. meaning washing out the high ph that gets generated by the hardening process of the cement (if i got that correct). so the tap water that i use to was it has a ph of about 8.5 and after about 1 hour the water in the bottom of the tank is about 10.3 ph. i will change the water tomorrow and see how long it will take to reach that level again.. .and will do notes on that in the next weeks (hope not months till ph is down).
im really happy how it looks in the tank, cant wait to start on the bottom part
the thing where i failed is with the plant spots, i could not keep the water holes open (should have used some rubber tubes for that, and they got quite small. not sure if i gona drill some holes and seal the inside with silicone or so. but i have to come up with something for that.
so if one wants watering holes with cement use rubber tubes to keep them open^^