Free Glass Thermometer! If you buy any Mr. Aqua aquarium from Marine Depot in July and August, we will include a FREE Hydra Aquatics Glass Hang-On Thermometer with your new tank. It’s a $14.99 value and we’ll include the appropriate size (5 mm or 8 mm) for the tank you’ve selected. We’ve got Mr. Aqua tanks available in sizes ranging from 1.5 up to 65 gallons. The long bookshelf style is extremely popular; we really dig the low-iron versions for their clarity. You don’t have to do anything like enter a coupon or whatever. Just place your order and our warehouse staff will take care of the rest. Thanks for shopping MD!