Looks right. I could not get to this sooner as my DNS took too long to recognize the server switch over. I could see your post, but I could not get to it lol.
Are using both as drains, or only one as a drain? I have a similar setup with a factory Durso. If you have only one drain, it is better to not have a valve of any kind on it. If you have two drains, then you should have the gate valve on one and none on the other.
Preference with this hobby is to use what is called "True Union" valves, otherwise to have a union on either side of the valve. This way you can remove the valve for service without chopping up you're plumbing. Generally not an issue with ball valves but WILL be an issue with gate valves.
Finally, it is absolutely important we use 100% plastic (PVC, ABS, PTFE, HDPE, etc) on our valves. That gate valve does not look like one of the reef safe valves. Do check the inside to make sure all parts are plastic. Any required metal parts must be Titanium. Screws and such should be stainless steel, preferably grade 316. I personally use the Spears brand gate valves:
Schedule 80 Spears Gate Valves will provide smooth, lasting operation while giving your aquarium a professional look. Gate valves are used for any application that requires precise control such as skimmers or silent overflows. Slip x Slip Smooth long term operation Precise tuning More...
I do not use the economy gate valves. I have a thread on here that shows why. A valve on my manifold plugged up and I was able to disassemble and unseat the valve, clean it up and put it back together - did not need to undo any plumbing.
That gray 90 to the flex PVC is incorrect. The barbed end of the fitting is meant to be used with vinyl tubing. The flex PVC is meant to be cemented into standard PVC fittings. Not sure if that is on a drain or return line, but it is likely going to come off at some point. I would remove that fitting and use the necessary PVC fittings to make that 90-degree turn. I would use a "Street 90" there and screw one end of the fitting into the existing 90 and cement the flex PVC into the slip end of street 90. Either that or remove the flex PVC and get a length of vinyl tubing and a hose clamp.
Street 90 - Threaded male on one end and slip female on the other.
One other thing, I think that the check valve you have in-line may have metal parts on the inside. May not be reef safe. If your sump is large enough to hold whatever water will drain back when the power goes off, then you don't even need the check valve. They don't always work anyway, so their use may just be false peace of mind.
Yes that check valve was not used. Ordering clear swing from BRS in the morning, just trying to see if it is schedule 40 to fit my plumbing. Need to put a new picture up. Also the barb and spa flex was used to water test in the garage, will be changing that to clear flex hose once I get the correct pump.
My first tank has been a DIY with very old equipment that will not die for over 10 years now. Finally getting to upgrade and trying to get it right. My husband is not into tanks but has been really trying to figure this all out from the pictures that I show him.
Thanks for all the help.
I missed this question. They are compatible for solvent/socket fittings. On threaded fittings, they are threaded to the same taper, but you have to use caution when threading a male Schedule 80 into a female Schedule 40 as it is easier to crack the female fitting that if you keep Schedules matched.