Growing Living Stones at 63rd Parallel North

i water my only conphytum. because of the growing algae problem i am ready to transplant the rest of my living stones. i first rinse pumice and fill the new pots with it. i carefully transplant the living stones and observe that i have 18 monilaria plants, 2 argyroderma plants and 3 lithops plants. i choose a shallow but wide container for the monilaria. it used to be a plastic instant food container. i plant the argyroderma and the lithops in clay pots. clay will help the containers to dry faster since i don't have so many plants left. i separate the algae infested pebbles from the old pumice and only boil the cleaner ones which i pack away to wait for further use. my monilaria plants my argyroderma plants my lithops plants

the monilaria (20) the lithops (4) the argyroderma (2) the conophytum (2) it's the 8th of january and the algae just blooms.  - they also turn black when they die...

i decided to start watering my living stones regularly twice a week. i spray them with water and every other time i bottom water and fertilize instead. my watering schedule for the month of november: on the 1st (sprayed), 4th (bottom watered), 9th, 11th, 15th, 18th, 21st and 26th. on the 11th of nov. i noticed that both of my argyroderma plants are changing their first leaves. almost all of the monilaria have already their 3rd leaves. they are growing very fast. my 2 conphytum plants or my 4 lithops plants haven't done anything yet. all of the containers have a lot of algae. on the 26th of nov. i noticed that the conophytum plants are also changing their leaves. my living stones are 3-month-old! towards the end of the month i began to lengthen the time between waterings and to reduce the light from the plant lamps to 10 hours a day. in the end of the month the temperatures dropped to freezing temperatures outside and the indoor heating started. therefore the humidity indoo...

the temperature is + 26 °C. the amount of light is the same as previously and the moisture ok so i don't need to water any of the containers. 22 of the monilaria seeds have sprouted, 8 of the argyroderma and 6 of the lithops and finally 1 of the conophytum seeds. i notice that the container with monilaria seeds has algae. it is the beginning of a worsening condition soon to be seen in every container. i am worried that later on when the conditions get dry the dying algae atracts mold which in turn could kill my plants. the other option is that the algae steals the nutrients and keeps the container far too wet so that the plants will rot. unfortunately transplanting my seedlings is not an option. pumice seems to be quite a comfortable medium for algae. it is dusty and porous. i don't know how other growers keep algae at bay.