Mealy or scale, it doesn't matter (my vote is for some sort of scale, Bois-duval maybe?), since mealy is a kind of scale and you treat them the same way. First line of defense is to wipe off all the visible pests. Next, spray with an insecticidal soap or horticultural oil. Keep at this for a while and that should take care of it. Be persistant, this kind of scale is insidious!

I don't know what kind of algaecide you're using, I assume you're dosing correctly. Most algaecides are tricky. Too much and the fish die, not enough and the algae doesn't die. When you say white foam and white globs it makes me think it is killing some algae. That doesn't mean it disappears. Like when you mow the lawn the grass clippings are "dead" but they still look like grass for days. Algae can stay looking like algae for weeks. Algaecide only kills some species. Mat algae and non-green algae seem to do OK. Algaecide isn't like chlorine in a pool. You can buy other chemicals like oxidizers to "burn up" organic matter. But again they're not magic. It's kind of a lot of work to get good results. To me in a 3000 gal pond vacuuming/scooping out algae and waste is way easier. My web page on vacuums. I consider Microlift type products to be a scam. The idea that bacteria have to be introduced into a pond is not something I can imagine. In this case you also have a bog where waste collects and extremely low (like zero) O2 so very slow to decompose. A bog can hold a lot of waste too so that's just a lot to handle even if you believe in such products. It's just way more effective to remove the waste from the pond than trying to somehow break it all down into nothing in the pond. Kind of a losing battle. But I know there are lots of people who swear by these products. And even if you do you dissolved organic compounds shoot way up which gives you other problems. The only thing I can think of is it must be expectations. Another person could have the same results as you and say the bacteria in a bottle worked great. Don't know what the deal is. Here is a link that might be useful: Bacteria in a bottle myth

Suzanne, does your plants have scale, too? Can you ID scale? Where will you shower your plant? In the sink or shower or hose? If you tilt the pot while hosing, bugs should fall off instead of inside soil. It sounds more difficult than actually doing it, but after a while you'll get the hang of it. Yes, hosing will wash off all sticky stuff and bugs. You don't have to apologize for asking questions, Suzanne..that's why we're here. Do you think you have a problem w/under or overwatering? Water soil when top 3" feel dry and look crumbly..anohter way to test is by lifting the plant..if it's light weight then most likely it's dry, if heavy then your citrus doesn't need water..The best time to weigh is just before watering..give a thorough drink then lift pot again..You can feel the difference in weight. Wet soil and dry air attract insects. It's a good idea hosing small plants in the sink once a wk. (it's actually fun after a while) LOL. Don't think of it as work, think about a healthy, bug-free plant. Daily misting also helps moisten the air, too. But detest humiidty. So, hose plant down, let dry..then swab (alcohol) over area w/white patches. Try swabbing all you can see..Look everywhere..bugs like hiding places like under leaves, between stems. If you have any other questions feel free to ask..Toni

It's called whitefly... a nasty parasite that loves hibiscus. The only thing to do is spray constantly, a systemic pesticide is best. Oil based sprays are probably effective too but don't last long. Spray often. If you don't spray your entire plant will have wisps of whlte cottony stuff all over it. I hate whitefly .... but it can be beaten. Is it what is in this link to pictures with whitefly? https://www.google.com/search?q=whitefly+on+hibiscus+image&client=palemoon&rls=Palemoon:en-US&tbm=isch&tbo=u&source=univ&sa=X&ei=4ObdU6CbKMz1oASgmoDYAQ&ved=0CB4QsAQ&biw=1536&bih=665 good luck. Mike