Yes imo esv is very good. Althou... Have found time and time again that colts and kenyas droop a lil, for a few weeks or so till thy adjust, whenever i switch back to esv. There is also more margin for error since it's a 4 part solution. Have also found it to be a bit on the low side as far as elements, which may speak to your issue.
While any brand can vary a bit batch to batch have found instant ocean reef crystals some good stuff a bit above average as far as elements. Pets aquatics in new hyde park sells it regularly for $40 for the 200gal box.
To see how much brands can vary, Check this out
Here is a list of what they measured for the big three in a number of the salt mixes we use today. This is intended as a guideline only. These numbers should be what you can expect from these salts mixed at 35 ppt or SG 1.0264 @ 25 C.
Well, may as well update. No true change, any soft coral (outside of one green mushroom) is extremely annoyed in this tank. Haven't tried different mixes yet but I'm considering the fact that my tank may be over stocked and probably needs to lose some coral. Iodine didn't seem to make any noticeable change and has been stopped.
I have a mixed 26 gallon tank, no sump all corals are doing wel for years .
I have a huge elagance, bubble, Duncan , gold torch and hammer and red gonnipora, also a green sps slimer grown from 1" to the size of a small hand, also recently I acquired gsp and pulsing Xenia also doing well,
Tank has a few fish , no clean up crew and green algae and gost anemones .
Point is I do 5 gallons a month water change, clean the skimmer weekly, and add a cap full of dry calcium weekly, alk buffer bi weekly and have not checked parameters in years,
Been using RODI for about two months now. Most recent SPS addition (monti cap) isn't dying (but I wouldn't say its thriving yet either). Put cespitularia in from my fathers tank (which was doing incredibly well by him and slowly but surely it's fading away in my tank). I'm beginning to wonder, now that I have RODI and can eliminate water contaminates (in theory) that it might be as simple as not having enough phosphate to sustain the life of soft coral. Is there a "best practice" for bringing the tank to a point where it can sustain soft coral life without bringing out a massive algae bloom?
some corals like the water on the nutrient heavy side, and some don't. As an example have seen zenia thriving in tanks with phosphate and nitrate way to high for many other corals to live.
Have also seen many tanks with way low nitrate and phosphate filled with lingering algae problems, while others with high levels with virtually no algae to speak of. Depends on lighting, what other nutrients are present, and what you have in the tank that is eating it or competing with it.
It may take some time before you notice a dif when using ro/di. Depending on what you were putting in the tank from your tap water. It may have soaked into your rock and sand.
There's so many variables. Like how much co2 is in your house, if any cleaning products or bug sprays you may use are effecting chemistry. Are there any contaminants on your hands, rock, nets, rock, etc. Are there any objects, like metals, in contact with the water that shouldn't be. Pests, stray voltage, the list goes on and on.