I use distilled. Was told by several people that it is just as good. If NOT then I can get RO water from a LFS in my area SG? Sorry I am still too new to know all the terms. I use Instan Ocean for salt, and will be doing more water changes. I have not done as many as I should cause I have had ZERO issues til now. Just topping off and everything has been fine.
Ok. There are several threads with stickies at the top of this "New to the Hobby" forum. Should give you a lot of info and terms.
SG is specific gravity, measures the amount of salt in your water. Stickies will also give you the range, and a whole lot of other info.
Your tank is 3 months old, and you have livestock, and you say have not done as many water changes as you should. There, in my opinion, lies the problem, and consequently the solution. With the inadequate water changes, you have steadily been accumulating nitrate and phosphate, and consuming your alk and decreasing your pH. I would do frequent water changes, something like 20% every week or more frequently. I would use a salt like IO Reef Crystals, which has a higher alk than Instant Ocean. I woukd keep the SG at 1.026, but that's my preference. This will gradually bring your nitrates down, replenish your alk and fix the pH, and also get rid of your phosphates. Once you've reached an acceptable state, you'll have to decide on a water change schedule among the wide variations seen in this hobby. Nitrates are usually a good measure of how often to do water changes. If your water changes are good enough to keep the nitrates down, they usually are good enough to keep your phosphates and alk in check. At least in a tank this young.
Dosing with chemicals usually is not needed until much later in the life of a reef tank.
Some say GFO should be used as early as you can to keep phosphates in check. But, that usually requires a reactor and associated equipment, and adds to the initial expense unnecessarily in my opinion. Stick to water changes for now.