While I prefer no more than 2 in a row, you can daisy-chain up to 3 cooltubes in a row, pushing them with a single 150mm axial blower. Each cooltube will raise the temp of the air going through the duct line by about 7C. If the cooltube intake air is 20C, the air temp in the duct after the first cooltubed lamp in the chain is 27C, 34C after the second, 41C (!) after the 3rd. If you put 4 in a row, the temp at the end of the duct line is 48C (!!). The glass on the (3rd &) 4th tube will get too hot and that heat is convected into the grow room air, negating the purpose of having them.
You want to run 4 lamps in cooltubes (which are 150mm dia), so you should use two, separate duct runs, each with a 150mm blower pushing cool air into the duct lines, with 2 cooltubes in each. This will keep the heat mostly in the air in the cooltubes' ducts instead of warming up the cooltube (and aluminium duct if used) exterior surfaces. Insulated ducting helps keep heat inside the ducts, but isn't essential.
WBW, ALL CAPS in one run-on sentence really doesn't make you any more readable! When you write in ALL CAPS- you are YELLING! PLEASE DON'T YELL AT ME!
While I don't expect you to be a professional writer, all the same, I don't want to have to work to decode your writing AND work to sort out your grow problems. Please use SENTENCES, such as I've done for you here in my quotation of your last post. The quality of my reply is dependent upon how well I understand your query. Clarity is everything. Make yourself readable- or make yourself scarce!