Go with what one will give you more height plant wise sometimes the longer ones are better,but i use a new one every year its a must,i think even more so if you are vegging big plants in hydro set ups where a lot of water is been used
I worked for a company that used to sell them and i took apart two of mine after vegging then flowering for 12 month,because humidity is higher when vegging it causes gaps in the charcoal so i would get a new one every year if you are doing real smellies,if ya just flowering i have humidity at 50 % they can last 2 year but ya need a ec unit and de humidi unit.
I am likeing the big boy filters,there not that expensive the rhino ones
[peace tyke]