With the right size fittings in hand, plumbing couldn’t be much simpler. Spend $10 for a tubing cutter to ensure clean, perpendicular cuts. Measure and mark tubing to Sea Tech’s insertion point line on fittings, leaving tubing a bit long to allow for movement, and also mark the existing pipe or tubing to ensure full insertion. Whale and SharkBite fittings aren’t marked, but tubing is. Cut at one mark and insert to the next.