Get new aragonite sand; it sounds like yours has lost its buffering capacity based on the pH (which needs to be at 8.0).
Keep the lace rock & Texas holey rock, and ditch the lava rock; you can use the lace rock & Texas holey rock as base rock. Buy some high quality dry reef rock & a small piece (don't even need a pound) of high quality live rock (make sure it has coralline algae); the dry rock is cheaper than live rock & should match the rocks that you already have, and the live rock will seed other rocks with beneficial bacteria & coralline algae.
Get a sump & ditch the canister filters. PetCo is supposed to be having their "Dollar per Gallon" sale, so you can easily get an aquarium to use as a sump for cheap; a 10 gallon will work, but a 15 gallon, 20 gallon, or 20 long are better options as they'll give you much more space. Saltwater is all about biomedia, and canister filters tend to turn into nitrate factories in this setting; a sump will allow for more live rock as well as a refugium for chaeto algae ("eats" nitrates & phosphates). If you don't want a sump, then HOB filters (AC 110s work nicely) filled with live rock rubble, Purigen, & chaeto algae (one filter for each media) will work nicely as well although you may have to replace the impellers after a while as saltwater can be hard on impellers.
Buy a protein skimmer. I can't stress enough how much easier it will make your life as it's the number one most important piece of equipment to have on a non-nano/pico saltwater aquarium.
It's okay to have the salinity at 1.023 for a FOWLR, but you'll want to take it up to 1.025-1.026 if you decide to go reef. Oh, and make sure that you're using a marine salt mix; plain old aquarium salt & other salts will not work!
Get a powerhead or two in order to improve circulation & keep the water well-oxygenated.
As for your lighting, at least get a dual bulb T5HO fixture & get a daylight reef bulb (maybe 10000K or more than that) & an actinic bulb as that combination will make the fish look their best plus it will let you grow coralline algae (the pink, purple, white, & lime green beneficial algae) on the rocks which in turn helps to prevent nuisance algae.
In short, if you go cheap on saltwater, then you will most likely fail & will get mad when spending a little more would have resulted in a system that pretty much runs itself once it's up & running.