4 Years Maintenance Advice

Hi All -- My 14 gallon Biocube has been chugging along for 4 years and I starting to wonder if there is some type of maintenance that occurs in mature tanks. The tank is in fair, but stable shape.

• CUC = A few turbos, bumblebees, and nassarius snails; hermit and emerald crab.
• Pests = A bit of bubble algae, vermetids, and unknown red algae (see pics); and cyno (just started)
• Livestock = 2 ocellaris; 2 zoas; 2 mushrooms; and 1 euphyllia

I'm trying to get ahead of the cyno by sucking it out and upping my water changes, which is bringing it under control. The other pests seem to be under control. I'm really not checking chemicals anymore as water changes seem to be the universal answer.

Questions:

1. My first thought is to change the sand. I've been sucking it out as it's getting pretty gross so there's not much left. Any thoughts on changing sand in an ongoing tank. Type of sand that is less prone to harboring waste/algae? I could go no sand, but I do like the look of sand.
2. What other types of maintenance should happen at this point?

Thanks for your continuing help. Hopefully get the tank ready for the next Grow Out contest.

 

Thanks. In hindsight, a 14 gallon was a bit of a rough intro to saltwater. Any thoughts on the algae. It's not growing very fast, but it looks nasty.