Unless your carbon dosing your not nitrogen deficient so don't worry about raising No3

As for gfo any phosphate removing media works , chances are yours is exhausted as it can only hold so much phosphate . The first batch is used in 48hrs if it's high Po4 then each batch afterwards will last longer as long as your inputs don't over weigh the exports

High phosphates inhibit growth in hard corals

A high alkalinity would actually get you better growth in hard corals coupled with a higher ph , but yours is a tad high leaves no wiggle room.

Lastly buy good test kits , your Po4 may not even be accurate if it's not verified ;)

Api is not good , buy some good test kits then you'll have a better plan . You can't do much on false numbers and Api is hit or miss on what test is worth trusting;)

I use a mix of elos , salifert and Hanna :)

How about magnesium? I think IO salt is generally a little low so you likely are as well. Several years back when I started running GFO and boosted Mg to fight hair algae the coraline algae growth really took off in my tank and the general stoney coral growth increased as well.

Aquarium Chemistry: Magnesium In Reef Aquaria
By Randy Holmes-Farley, Ph.D.
http://www.advancedaquarist.com/2003/10/chemistry

Mag has never been a limiting factor for me using IO. I did start adding it with my new build, but can't say I see any difference.

Ok, so plan of action is, new test kits. Have to order some or wait till I hit the big city next. I don't think my LFS has anything else other than the API I already have. Have to call and check. I had no idea the GFO was only good for a few days on the initial go round. The bucket says it good for a couple of months before needing changed out. I will re-start that off tonight. Thanks for the replies everyone. Keep the ideas and knowledge coming. I'm learning as I go and every little bit is sure welcome!

it can last for weeks and longer so they choose their words carefully and technically they are right , but its dependant on the phosphate level that are current in the tank , if they are high then your media is going to bind a fair amount of phosphates and thus get exhausted pretty fast, if they are low then it will bind some as the levels increse over time and then be exported later.

you can measure the output of the reactor it should be less than the display, if it is more than that , it is exhausted.

at about 300gph turnover through gfo reactor your going to turnover your whole tank a few times a day , so the first initial batch will get used up very quickly.

once numbers get down a batch can last longer depending on your phosphate source.

if you are running it passive then you can be getting more bang for your buck with a fluidized reactor.

the reason why it is hard to become nitrogen deficient is simply the imports of foods and fish waste/ ditrius buildup has to be exported faster then they are added.with smaller systems this can be achieved by water changes too often and too large using good source water ,low biolaods or no bioloads etc. but in an average ran aquarium water changes are weekly/ or longer and the buildup of of nitrates is daily so therefore corals are getting what they need daily as they build up.

with Po4 alot of people use gfo or other binding products and run it 24/7 so you can become phosphorous limited , but the additon of daily foods keeps it in check unless the limits are pushed.

so if you were to add a removal source for nitrates that was daily that can out compete your daily inputs of n , like bacteria can, then you can become nitrogen deficient:)

I wouldnt trust that api kit. I also have one kicking around and my tank also measures .25 but if I use any other trusted kit, my readings are undetectable and I dont use any gfo either.
For the longest time I just kept changing my gfo cuz it always gave me a false reading until I bought a good test kit.

About coraline algae, not having any doesnt mean much. Ive never had coraline algae grow in my tank and growth has always been awsome. Theres a few amazing tanks online who never get any coraline algae either.

Wait till your test kits come in and go from there.

Agreed. IMO, it's a nuisance algae.

I would also suggest you get better test kits. You say that you're using Instant Ocean salt, but you make no mention of dosing calcium, alkalinity, or magnesium into your tank. If you are not dosing, then those number are certainly not accurate. If you aren't dosing, and you prefer to hold off dosing as long as possible, I would suggest you switch to H2Ocean salt as the numbers are better out of the bucket. Instant Ocean is low in calcium and magnesium out of the bucket which isn't a problem if you are dosing, but it is a problem if you want to avoid dosing.

My personal preference for test kits is as follows:

Calcium - Elos
Alkalinity - Elos or Hanna Checker
Magnesium - Salifert
Nitrate - Salifert
Phosphate - Merck or Hanna Checker

What are you using to test specific gravity? Have you checked temperature in the morning before lights go on, and in the afternoon at the end of the peak lighting? I'm wondering what the temperature swing is. I would also double check with a second thermometer. Pick up a TDS meter too - they are only about $20 max. What's holding you back from installing your RO/DI at home?

If reference to the high phosphate reading - IF (and that's a big IF) the number is accurate, then take a look at how much you are feeding the tank. Are you feeding any liquid foods? Do your fish all eat pellets? If so, switch to pellets and just feed frozen foods 1-2 feedings per week. First, confirm the phosphate level though. I don't think you mentioned what kind of skimmer you're using? It's also unusual for the phosphate to be so high and nitrate to be so low, so I'm guessing that one or both of these readings is inaccurate. Is there nuisance algae growing at all? Don't use too much GFO, small amounts changed more frequently works better in my experience, especially in tanks with high phosphate. A common amount I use on client tanks is around 1 tbsp per 30 gallons changed out every 2-3 weeks.

Solid advice right here!