@ NightKev - Thanks for the response, all that makes sense and I had a feeling the portal guns weren't causing any issues after the see through feature being removed...What sucks is that it's hard to convince the other guys on our server that what they thought was causing server lag really wasnt.
Oh and by open world pumps i just meant pumps in general. Example, when we started out we had a pump in the ocean...over time, it was sucking the source blocks from the shore and made that shore look like it had more and more moving water. I'm not 100% if that caused lag but it might have...jsut like i've heard that sucking that lava out of the nether will cause the same effect over time.
Oh and by open world pumps i just meant pumps in general. Example, when we started out we had a pump in the ocean...over time, it was sucking the source blocks from the shore and made that shore look like it had more and more moving water. I'm not 100% if that caused lag but it might have...jsut like i've heard that sucking that lava out of the nether will cause the same effect over time.