just my opinion, but having dealt with Dino's previously, I wouldn't add snails. They'll most likely die and cause more nutrients. When you do want to add snails, I cannot recommend reefcleaners enough, for a few reasons. First, you get great value; Second, you get healthy specimens, and Third, you get pest free specimens.
I ordered 15 trochus snails from LiveAquaria, and since I hadn't quarantined inverts before, I wasn't going to start now. 4 months later, I had vermetid snails all over my rocks, and I'm sure was from a hitchhiker from the LA order as the only coral I had put in at the time which was on a frag plug was an encrusting montipora, and I couldn't remove it without destroying the frag...not to mention that frag came from boom corals, who I trust in terms of pest free stuff.
Reef Cleaners, along with Algae Barn keep their snails in fallow systems, meaning, no fish. No fish = no fish diseases coming along for the ride (ie: Ich, Velvet, etc). Scrub the shells with a wire brush, and in they go.
I would continue along the path that
@dantimdad and I have given you...lights out until Friday (Saturday morning), skim wet, and change your socks out daily. This will help kick the butts of any algae in the system whether it be dino's, bryopsis, hair...do your 20 gallon water change. run lights a few hours (4), and keep changing the socks out. When you do your water change, you can siphon out a lot of the decaying algae.
Wait 2 hours, test. At this point, start making another 20 gallons of rodi. 3 days from the test, do another water change, and test afterwards (2 hours).
Let's get to Friday/Saturday and then tackle things.