you can use the lava rock over and over. It is excellent bio-media, but some people don't like to use it because it is heavy. Plastic scrubbies work just as well and are much easier to handle. Commercially made bio-media is also excellent, but not nearly as inexpensive. Rocks in the pond are a trap for fish poop and uneaten food. The rotting debris just sits there, in the bottom of the pond, contaminating the environment that the fish live in. I personally hate rocks in the pond because it is unhealthy for the fish and is very high maintanance. If you do have rocks, a yearly clean-out is a must!! I prefer fall clean-outs though, so that the fish can over-winter in a clean pond. Fish are at their weakest in winter and early spring and a healthy, clean environment means less spring start-up health issues.

There is nothing wrong with your tree. Falling leaves from citrus is quite common at this time of year, and for the next month depending where you live. The leaves in question are just old leaves that have lived out their life span A citrus leaf has a life span of 20 - 24 months. If you look at the leaves you can even see where the tree has pulled back out most of the remaining nitrogen from the leaves so that the nitrogen can be reused before the old leaves are discarded. When an older citrus leaf can no longer accomplish it full required work task for the tree it is quickly discarded. There is no welfare program for an old leaf. Adding gravel, rocks, or other such material, does NOT help with the container's drainage. It actually hurts the drainage, because the layer of rock only raises the perched water table even higher into the container's growing area. There a all types of mediums that a container citrus will grow well in. Just be sure that it has good drainageand good aeration. The number one potting mix world wide for container trees is 5 parts conifer bark, 1 part coarse sand and 1 part peat moss. It is used by most every commercial nursery in the world. This forum has two favorite mixes that they seem to use. Personally, I have never use them, but for small trees in small containers they seem to work. Good luck to this tree. - Silica

Msgirl asked very good questions that I always learn from her. Sam, thank you for the reply. Looking at Hawaii's rose park: vivid & deep color, indicative of DEEP & fertile soil rich in volcanic ash. Plus roses in public parks are GRAFTED on Dr. Huey which can reach deep below for nutrients. Chicago Botanical Gardens' hybrid-tea roses are grafted. Even with their loamy fluffy soil: their Old Garden Roses (most are own-roots) can't go down deep ... and their blooms become 1/2 size in our record-rain this year, due to calcium & nutrients leaching. It's worse in my heavy clay, only 1 foot of top soil, below is ICKY sub-clay that no plants can grow, not even weeds. With wimpy own-roots, really tiny like alfalfa sprouts, in 1-foot-soil, and 40 inch. of rain, plus 32 inch. of snow per year ... that will leach out nutrients UNLESS solid stuff is added on top. I see own-roots like babies: if they are really tiny like Jude the Obscure, they can't handle solids, and have to be spoon-fed constantly with tiny, diluted amount of SOLUBLE fertilizer ... tiny roots can't hold much at one time, and die if too much is given. That's why slow-released organics, low NPK 2-1-2 & low-salt like alfalfa works well with own-roots. Re-mineralization on top works for own-roots, since they can't reach deep down. Even with aggressive own-roots like Romantica French roses: it's thick & woody surface roots, rather than a straight stick down like Dr. Huey. Frederic Mistral died after many years in my garden, when I dug that up, thick & woody, but within the top 6" of soil ... I put 1 bag of sand, 1 bag of organics, and 2 bags of top soil. The soil is deep & fluffy & loamy soil ... it's just the nature of the root expanding across, rather than a straight stick down like Dr. Huey. Mirandy is known to survive zone 5a for decades, when I killed it on purpose, the root was a straight-stick deep down, very much like Dr. Huey. Dr. Huey is a huge & woody straight-down stick. He doesn't need to be fed nor watered that often. Dr. Huey is so aggressive that within one month of planting, it reached deep down to the sub-clay beneath, I broke 1/4 of Dr. Huey when I dug up Pink Peace ... but the rose was perky after I re-planted. So re-mineralization is NOT needed for Dr. Huey, he can extend 4 feet across to steal water and nutrients from elsewhere. I spent 1 and 1/2 hour killing Dr.Huey rootstock. Yes, the root extended that far: 4 feet across, and at least 2 feet deep. Someone in Colorado reported killing Dr. Huey, and 5-years later, it sprouted again. My neighbor spent $$$ to have a tree chopped down, but they did not dig up all the roots. Few years later, I saw a bunch of shoots where the tree was chopped off. My zone 5a is infested with ugly, tall Dr. Huey take-overs . Homeowners don't have the time to kill Dr. Huey.

MsGirl: Marine Cuisine with NPK 10-7-7 has both organic materials and chemical nitrogen. Here's the ingredients: " Cottonseed meal, blood meal, earthworm castings, fish meal, shrimp meal, crab meal, bat guano, seabird guano kelp meal, urea, ammonium sulphate, calcium nitrate, ammonium phosphate, Treble phosphate, potassium sulphate, potassium chloride, ferrous sulphate, iron sucrate, manganese sucrate." The ammonium (chemical nitrogen) in Marine Cuisine is what makes more leaves than flowers. Quick chemical nitrogen isn't best as solids, since that burns in hot weather. SOLUBLE chemical nitrogen doesn't hurt much in hot weather, if one use 1/2 teas. per gallon, that gets flush out with water (nitrogen mobility is a 10). But chemical nitrogen in GRANULAR, solid-form really burns in hot weather. Chemical nitrogen plus slow-released organics is a bad-combo, I burnt plenty of roses with NPK 10-5-4 (has chemical nitrogen plus chicken manure). Kelp is much higher in salt in spirulina, that's why when I read the negative reviews for Maxicorp Kelp powder (soluble), one person gave it thumb-down, citing that he/she got better result with spirulina. I tried spirulina before in protein-shake: very low-salt, and gave me energy. My neighbor lost A LOT of weight with that protein-shake. Spirulina is better for plants, since it's higher in iron & more nutrients, plus MUCH LOWER IN SALT than kelp. An excerpt from below link: "Spirulina avoids the sodium problems of algae that grow in the sea, yielding only 0.2 mg of sodium per tablet. All Natural Hawaiian Spirulina Pacifica is a pure natural super greenfood, containing protein, betacarotene, and essential vitamins & minerals. Spirulina has 2300% more iron than spinach, 3900% more beta carotene than carrots, 300% more calcium than whole milk, and 375% more protein than tofu. " http://www.amazon.com/Nutrex-Hawaiian-Spirulina-Pacifica-16-Ounce/dp/B0039ITKR4/ref=cm_cr_pr_product_top?ie=UTF8 Some people are allergic to spirulina and develop a rash. I didn't have any problems with that. Amazon reviews stated that Spirulina powder is nasty in taste, so it would be great for plants. http://www.naturalways.com/spirulina-analysis.htm