Yup no filter, any reduction in airflow will reduce the cooling effect.... Unless you have an über powerful fan of course!
The cooling system should be run on a separate circuit for optimum results, suck in cold air from outside and blow it down through the ducting to your cooltube(s) and then out through ducting to outside again. By outside I mean outside room/box, not necessarily outdoors!
By doing it this way you cam be sure that your cooltubes are doing the best possible job of taking away all that excess heat! Afterall that is why you bought cooltubes in the first place The 2nd reason to have your setup like this is with a closed cooling circuit you are able to more closely control the atmosphere of your room/box and as such can look at CO2 dosing etc etc.
Any extraction or intake of air directly into the room for the sake of air circulation, odour control etc etc should ideally be taken care of by a separate fan. Thenvonus being that as the 2nd fan is not having to do much work to keep the room cool you can use a relatively low cfm item to do the job.
The cooling system should be run on a separate circuit for optimum results, suck in cold air from outside and blow it down through the ducting to your cooltube(s) and then out through ducting to outside again. By outside I mean outside room/box, not necessarily outdoors!
By doing it this way you cam be sure that your cooltubes are doing the best possible job of taking away all that excess heat! Afterall that is why you bought cooltubes in the first place The 2nd reason to have your setup like this is with a closed cooling circuit you are able to more closely control the atmosphere of your room/box and as such can look at CO2 dosing etc etc.
Any extraction or intake of air directly into the room for the sake of air circulation, odour control etc etc should ideally be taken care of by a separate fan. Thenvonus being that as the 2nd fan is not having to do much work to keep the room cool you can use a relatively low cfm item to do the job.