I feel like I’m fighting a loseing battle with my tap water being so high I have access to RO water at work but have been reading don’t start using it as it so much extra work Is there a way I can filter the tap water ? And if I mix RO with tap water do I need to re minarise ?
RO isn't really a lot of work if you have your own RO unit, but if you have to transport it from elsewhere it can be a problem.
Depending on whether you have any particularly sensitive fish, nitrates up to 20 ppm above tap water level are acceptable, so what fish do you have?
If you mix RO with tap water you may need minerals as well depending on how hard your tap water is and what fish you keep so please post your water's gH and kH so we can help further. If you don't have gH and kH test kits, post your pH and look on your water supplier's website for your hardness. You should find you can type in your postcode and get a report for your local area which includes hardness.