New fish are already stressed from being captured, transferred, & keep in sub-standard conditions. Why add to it with trying to quickly acclimate them to a sg/ph change that can be as much as 0.006 in sg and 1+ in ph. Divers slowly ascend when diving at lower depths to keep from getting the bends & I also feel fish/inverts need time to adjust to their new tank parameters.
IMO keeping the qt tank sg the same as the main can be too stressful for newly acquired fish/inverts unless you keep your main at 1.019-1.022 sg which is where most fish stores/online places keep their sg at.
If you keep your main closer to 1.025 sg then even
drip acclimating for 2 hours can be stressful and can possibly cause osmotic shock in fish/inverts with the rapid change in sg/ph leading to sickness or death depending on the change in sg/ph that the fish was kept in.
Personally I keep my qt tank at the same level as the lfs (ph 8.0 sg 1.019) and slowly raise the sg/ph to the main sg/ph of 1.025/8.3 over the course of 3+ weeks per
this article in advancedaquarist.com.
The use of a
refractometer is highly recommended while performing any sg changes whether if it’s matching lfs sg level or main sg level to the qt tank. Adjusting the sg down is less stressful to fish coming from that environment and slowly raising it a little bit every other day gives them time to adjust. Since you have to keep them in the qt tank for 3+ weeks anyways it just makes sense to me to provide a less stressful environment.
Lastly I’d get a 20+ gal qt tank instead of the 10 gal. As Brenden mentioned a pwc of 20+% would probably need to be performed on the 10 gal often even using the transferred filter from the sump. Also I always keep 20 gal on hand of well aged sw during any qt procedures in case of emergency.