I am by no means an expert but I have recently switched to coco coir and I can tell you that if you're using calcium nitrate then you shouldn't really have any problems. Also depending on what brand you buy, they are sometimes already pre-buffered with calcium nitrate and some micronutrients already (botanicare brand for sure all come pre-buffered). I have also tried the cheaper stuff (Plant!t) coco bricks from amazon that were about $11 per 5kg brick and I would say that probably was not prebuffered so I broke chunks off into a large pillow case, rinsed it well and then soaked it in a bucket of calcium nitrate and low strength hydro nutrients for a few hours and that should buffer it.

As far as your choice of nutrients, it is a bit high in the K considering coco is naturally high in it. I would make sure to water and get 20% runoff each time to make sure there is no build up of salts in addition to the naturally high K.

You may want to look at something with less K in the future, JRPeters Hydroponic 5-12-26 is very popular. Peters 5-11-26 is a lower quality but much cheaper alternative as well. Either would probably be a bit better for use in coco than 4-18-38.

Thanks so much i was thinking it was a bit high in k. I haven't purchased masterblend yet so i might switch to something less in k

You can order Jacks 5-12-26 here: http://www.jrpeters.com/who-are-you/hydroponics/shop-now.html - I get my calcium nitrate from here: https://customhydronutrients.com/calcium-nitrate-greenhouse-grade-4-pound-container-p-73.html?cPath=1_44_62_373&zenid=0312eeff1ecd32176ecaff2c0b0ddfc1

If you don't want to spend $40 then you could try the Peters 5-12-26 which is almost the same formula (they used to be the same company) but they do use lower quality ingredients and less clean as well (more heavy metals). But it is way cheaper. https://customhydronutrients.com/hydroponic-special-51126-one-pound-p-88.html

With both you make a concentrated solution by dissolving 880 grams per gallon (or 220 grams per Quart) of the Hydro Special stuff and then 580 grams of calcium nitrate per gallon (or 145 grams per Quart). They have to be mixed separately as calcium reacts with sulfur if they are in concentrated. 15ml per gallon of each is around 1.5 EC - adjust accordingly.

I think I am going to go with Peter's brand because this is my first indoor growing experience and the price tag is getting pretty hefty as it is. Thank you for the links and ratios.

I also found this ratio which seems less concentrated then the one you posted but has added mgso4

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"To make a working solution to be top fed, dripped or used in flood tables mix the following:

1.89g/gallon Peters Professional 5-11-26

1.84g/gallon Yara Liva CALCINIT Calcium Nitrate

0.94g/gallon Magnesium Sulphate (Epsom Salts)

Mixed together this will deliver PPM 100-24-108-93-25 (N-P-K-Ca-Mg)"

If I did my research right it looks like peters still needs some extra Mag. Also do you use tap water with your nute solution?