Is it ok for me to do this?

When i set up my tank which is a 40 gallon/180 litres
can i add 75% of tap water which has be declorinated and 25% of ro water the add the salt mix just to cycle it?

Once it has cycled i will remove 25% of the water and add another 25% of ro water.

As i cant afford 180litres of ro water at the moment.
I will use ro water in the future for every water change tho.
I just can afford right now for 180 litres of ro water as my lfs sell 25litres of ro water for £5

 

Well its pointless to mix the RO/DI and with the tap water to begin with. If youc ant fill it compeltely with RO/DI then this is what i would do.

Fill with dechlorinated tap water. While you cycle leave the lights off and run a phosphate remover. I would probably run the skimmer to from the start if your filling with tap water too.

 

how do i run a phosphate remover?

 

Are you planning on keeping a reef tank?

 

im just planning on keeping live rock,live sand,fish and 4 cleaner shrimp

 

Well in that case then phosphates arent really a concern, its only really a concern for algae control and coral health.

 

so will i be ok to do this?

 

Yeah course. Still, dont turn your lets on while you cycle. I know its tempting to, but if you leave them off you'll prevent alot of algaes from growing.

You may want to consider running something like Phosban or rowaphos in your external filter - but if its going to be a FOWLR then i prob wouldnt bother getting a phosphate reactor.

 

with me using ro water for every water change ,over time there shouldnt be any tap water in the should there?

also is algea growth bad?
i will be adding 4 cleaner shrimp in total but only 2 at a time once the tank has cycled and with a month apart.will they clean any algea growth?

 

cleaner shrimps dont eat algae in general Chadley
their name comes from the fact they will clean fish of dead skin and some parasites

for algae in salt water tanks , you want snails and hermit crabs
but again, even these guys can be overworked if you allow to much algae to grow

Phoenix heights advice about not using lights, while your tank cycles , is spot on IME
That way if in 1 months time, you add snails , hermits etc, they should help keep on top of the algae for you

water changes with RODI over time will help for sure

Steve