Tidehunter

What do you do with the Iron Branch & Gauntlets of Strength in starting items? Sell them? If so that's a waste of your starting gold.
You would be better served with a Clarity instead of the Iron Branch as Tide doesn't even have enough Mana to cast Gush twice for the first few levels.
Why a Ring of Basilius? Urn of Shadows would benefit Tide far more and make use of the Gauntlets of Strength you purchase with your starting gold. Hell even a Bracer would be useful & not waste the gold you spent on the Gauntlets of Strength.

Things you don't list in the items which you need as a support Observer Ward, Sentry Ward, Dust of Appearance & Smoke of Deceit. Also your text mentions Blink Dagger but the item build doesn't list it.

Why take stats at 14 & 15 if you're going to get level 4 Anchor Smash at 17?
Why take level 2 Kraken Shell at 7 instead of level 4 Gush?

You don't seem to get what "Core Items" means in the Dota community. Core is what you're calling "Main" while what you list as "Core" would be called Extensions.

Power Treads wouldn't be a useful extension for a support Tide. Late game you would want to disassemble the Tranquil Boots & build Boots of Travel. Also a support tide is very unlikely to have enough gold to build either Refresher Orb, Bloodstone or Assault Cuirass so out of your extension items Blade Mail is about the only one worth considering.