Most of my parameters are a little off...

[Littlepip]

Hello guys! This is my first post here. My tank is a couple years old, 300 Litre/80 gallon with a sump. I've lost some control the past year due to university and work, but now I am wanting to get back on top of it all. I lost most of my corals over the course of the year, but I still have 2 very happy bubble colonies and a lot of mushrooms (which are splitting and growing at an alarming rate lol). I've sadly lost my Euphyllias, which I most want to be able to keep. My parameters are as follows:
Salinity: 1.026
Temperature: 26Celsius/78.8Farenheit
pH: 7.7 (salifert was about 7.5 but I have trouble reading it. API was about 7.9) (also this was tested in the evening)
Alkalinity: 14dKH
Calcium: 460ppm
Phosphate: 1.0+ (the nyos chart didn't go high enough) (I'm probably overfeeding, trying to get my mandarin fat)
Nitrate: 35ppm

As you can see, most things are a bit off, with phosphate seeming pretty scary! Despite that, the 2 coral species I do have are positively thriving. I am wondering what I should try and tackle first. Before I tested, I was expecting to need alk and calcium supplements, but it seems after a generous water change they're even higher than I need. I'm not even having much algae growth, I only scrape the glass once a week at most to keep it crystal clear.

Should I just do more regular water changes to balance things out? Is there a particular parameter that would be fine for bubbles/mushrooms, but toxic to Euphyllias/gonis? Or is it more likely a combo of everything, adding up to a big problem?

 

[blasterman]

Unless you are dosing calcium and alkalinity those numbers cannot be higher than what your salt mix defaults to because they can only go down. Logical, correct?

No salt mix defaults to 460 calcium and 14 dKH. Reef Crystal's is one of the highest with some batches ive used being around 13 alk and 420 calcium.

Which leaves testing error, and since API is in the equation I'm going to make a leap and conclude your alk and calcium isn't that high.

Which leaves nitrate and phosphate, which it sounds like are indeed pretty high. Soft corals like mushrooms, xenia, most zoas etc will love those super high nutrient levels. LPS and SPS won't like it.

Water changes are the only immediate way to bring those nutrient levels down, but its not a practical method to keep them down. Gets expensive.

A good skimmer, moderate your feeding... did I mention a good skimmer?

We then get into things like chaeto in your sump, and my fave: bio pellets. All these things help beat down nutrients.

 

[Littlepip]

Unless you are dosing calcium and alkalinity those numbers cannot be higher than what your salt mix defaults to because they can only go down. Logical, correct?

No salt mix defaults to 460 calcium and 14 dKH. Reef Crystal's is one of the highest with some batches ive used being around 13 alk and 420 calcium.

Which leaves testing error, and since API is in the equation I'm going to make a leap and conclude your alk and calcium isn't that high.

Which leaves nitrate and phosphate, which it sounds like are indeed pretty high. Soft corals like mushrooms, xenia, most zoas etc will love those super high nutrient levels. LPS and SPS won't like it.

Water changes are the only immediate way to bring those nutrient levels down, but its not a practical method to keep them down. Gets expensive.

A good skimmer, moderate your feeding... did I mention a good skimmer?

We then get into things like chaeto in your sump, and my fave: bio pellets. All these things help beat down nutrients.

I bet you're right! Totally slipped my mind how old my test kits were getting. They're not quite expired, but some have started leaking regardless....
I have an octo int 110 skimmer which is fantastic, I think it's just failed to keep up with my feeding and that's cumulated over some time.
Guess I'm gonna be mixing some water for now, and being more mindful with my feeding! Thanks for your advice.