CFM = cubic feet/minute, in simple term is the amount of air it moves per minute.

i think the best compromise in term of size vs CFM is still a 12v 8x8x2.5cm DC fan (normal PC ventilation fan)

n about evaporation, i think i read it somewhere, the principle behind cooling an aquarium with a fan is by promoting more evaporation. like wiping sanitizing alcohol on ur hand. when it evaporates, ur hand becomes cool right? so more evaporation =  more temperature lowered.

i think water evaporation is a price to pay for cooling an aquarium with fan. my aquarium has a surface area of 16x13 inch, water from my aquarium evaporates approx. 1cm per day. im using a single 8x8x2.5 12v DC fan only. it is suffice to lower my aquarium temp from 30-31 deg C to 25-26 deg C, n sometimes in the morning it can go as low as 24. i dun even hav AC in my room...hehe...

additional reading : read here if u really into DIY

remove the plant from the tank and use activated-carbon in the filters.
Be aware that some of the surviving shrimps may continue to die in a week or more even it seem ok now in another tank,
as happen to me last time. 

mind share where you brought this plant?

E.Aqua Midvalley, the pesticide leeched plant i also got from E.Aqua but from their Tmn Tun Hussien Onn branch.
Guess their supplier never listen to the complain.
Nowadays when i buy plant from any LFS i will put into a bucket and throw in 6 grass shrimp to test first. If got pesticide they will die in < 10min one by one or all in one shoot if very posionous.(that the main reason why i keep a bunch of grass shrimps as pet. 
Those pesticide won't affect fish much but deadly to shrimps/crabs.

I remove the carbon after one week and put in a bag of 100g Seachem Purigen to remove organic pollutant and polish the water.(Really Good Stuff).

Seachem purigen , can get from hehe- East Aqua Ikano branch(other branch don't have cos i nag ikano branch to restock - still got 2 box 100g left since i brought 1 more to keep) , Natural Aquatic World (aka NA subang got like 4 box 100g and the 250g bottle type, (if u buy the 250g bottle u need to get ur own filter bag as purigen media is very tiny in size, get the smallest pore size filter bag), ALL THE 100G come packed in filter bag - easier) , Aquatic Paradise in kajang got 2 box.

AI , 88 pets mart , Nilufar , Qian Hu ,all DON'T have(one of them don't know what is purigen -hahahahaahah) although they claim as one of the BIGGEST LFS in malaysia   

Cheapest i can get is RM45 after discount for the 100g purigen , if u can get it cheaper let me know which LFS.

O almost forgot to tell u, DON"T use any amine based polymer dechlorinator with Purigen , it will not foul the resin but will render it non-regenerable.
I change to Seachem Prime bcos of that and i love it. It didn't smell and stain my 11 liters mineral water bottles like API stress coat.

taken from seachem website:
Q: Does AP Stress Coat foul/ruin your Purigen product?

A: If they use an amine based polymer it will not foul the resin but will render it non-regenerable. What amine based polymers will do is bond not just to Purigen but to any organic scavenging resin as well as any ion exchange resin and when you attempt to regenerate the resin they will then bond with the chlorine to form chloramine which can be released into the aquarium. This is not just an issue with Purigen but with all resins being sold in the pet trade. The problem only occurs when one attempts to regenerate the resin, there is no problem unless you wish to regenerate the resin you are using. Seachem products do not contain amine based polymers and are safe to be used in conjunction with not only our resins but also with other companies resins.
http://www.seachem.com/support/FAQs/Purigen.html