If the proposed system is for filtration and desalination, the price of 2900 QAR is expensive. it consists of skid mounted small water pump, 4 stages cartridge and carbon filters, reverse osmosis membrane and small pressure tank (ultra violet disinfection lamp can be added).

In general sea water is desalinated using reverse osmosis or distillation system process to reduce the salt levels, however this process sometimes can not control precisely the value of each of the salt and therefore some salt reduced to less than the favorable levels but in general it is OK.

Adding that small water desalination and filtration system to the sea water desalinated system (tap water) means further reduction of some salts to unfavorable levels.

however, If the proposed system is only filtration system (without reverse osmosis membrane)it will be fine and will filter the water and remove residual chlorine, organic matter, bad taste and Color IF presents in water.

I have one small desalination and filtration system in my home country Syria where we get the water from springs/shallow wells. In this case the filtration system is good as it reduces the salts from higher acceptable values to the normal acceptable values ( I can live without it).