Integrity of old acrylic 300 gal tank

[bbehring]

I have a buddy that has a 14 year old 300 gal acrylic tank (72"lx38"hx24"w exclusive of side overflows) and 45 gal sump. We are going to start re-vamping the equipment (pumps, sump and lighting primarily) and were wondering how long the acrylic glue, bulkheads etc would last. My thoughts are while we are completely changing out the plumbing/pumps, we should replace the bulkheads on the tank and possibly look at a new acrylic sump?

Also the original 3 pumps which are all little Giant 4-MDQ-SC will need to be replaced. All are plumbed outside the sump, under the tank, within the stand, with bulkheads through the base front side of the sump. Although these pumps have stood the test of time (14 years) I'm guessing that there are better external pumps on the market now that are more efficient and throw less heat? He would like to plumb same flow pumps and not change out the overall design (1 - supply from the sump to the chiller and returned to the tank; 1 - supply from the sump to the tank (recirc flow only; and 1 - supply from sump through ocean clear filter and back to tank). I agree that this is not the best flow design and if it were me I'd re-plumb very differently, but the tank is built in to the wall with view from both sides (wall on end) and the overflow area at each side is very restrictive for arm reach. Which brings me to another delima, I need to replace the original, 14 year old plumbing retruns with in the overflows as they were plumbed with vinyl tubing and plastic clamps which have degrgated and split 2 of the return line sets. I don't think I can get my arms into these tight overflows. Any ideas in changing out the plumbing in these areas? I'm guessing the plumbing was installed after the tank was glued together.

Also while the tank is drained we are planning to buff out the scratches (which are numerous) Which scratch removal kit or process is the best and easiest to work with that can take out both deep scratches and feather scratches? All scratches are on the inside view panels.