I hate to jump into a party late... but I feel the burning urge to contribute.
Please don't feed this tree Miracle Grow of any variety... In fact... not feeding it right now is exactly what I would do. If you feel you must... then do NOT feed it anything with nitrogen... and get as mild as you can... 0-10-10 would be about as high as I would go. That or organic slow release ferts like BioGold which slowly melt into the soil as it is watered.
The reason is that nitrogen is going to trigger a growth response in a tree which has NOT had any kind of dormancy so far this year, and is in severe distress. To trigger growth when the tree has no stores and little energy would be to strip it of what little it has when there isn't enough warmth and sunlight to create any return for that effort.
By feeding 0-10-10 (if you must) you at least are feeding something which will create stronger roots, which will be a help in the long run if the tree survives.
I would stop soaking it for 20 mins... that's a treatment you would do to soil which is severly dehydrated. In your case, you are just waterlogging it. Watering from above is my own personal prefered method because it tells me a lot about how the soil is draining... and how dry it is. Soil which has the right amount of moisture in it still readily accepts and releases water. Overly dry soil will not allow the water in very quickly. Also the action of soaking in and flowing down draws air with it which is vital to the roots.
Remember... roots take up vapor... not water itself. If there is no airflow to the roots, they will drown.
Also... if your tree has been in doors for 6 months and you have bugs, you likely have a pest which is causing harm. It's fairly common for trees kept indoors to get them, and you should make every effort to try and identify them so you can treat it correctly. You live in SF which has one of the most active bonsai communities in the country. Google for a local club and take the tree to them. They will be able to help you.
Since you have a couple months left until it really warms up, it may have a chance to achieve some tiny level of dormancy (as minimal dormancy is achieved at less than 50 degrees), so let this tree be outside and give it no more than filtered sunlight. Since it has been indoors so long, none of its foliage will have the waxy coating most trees get which will defend it from UV light. Last thing you want to do is give it a sunburn... and believe me it will.
It is only with the greatest respect that I disagree with my good friends here... but I also happen to live on the west coast, and am pretty familiar with your growing conditions, and how junipers react here.
Important thing to know... don't expect much from the tree this year, and infact your only job is to coax back health to a tree. I once gave a tree to a neighbor as a gift for 3 weeks... and he gave it back nearly dead... I'm still coaxing it back to health, but several branches were killed completely.
As the saying goes.... Bonsai can outlive you with correct daily care, and not last a week without it.