Marine Depot offers FREE economy shipping for most products when you spend $29 or more! Your order will be delivered in up to 7 business days after it ships out. Economy shipping methods include UPS Ground, USPS First Class, and/or SurePost. You can also upgrade your shipping to UPS Ground which speeds delivery to 1-5 days. A shipping upgrade is $2.99 for orders under 20 lbs, $3.99 for orders 21-40 lbs, and $4.99 for orders over 41 lbs. Orders placed before 10:30 am PST Monday-Friday are shipped the same day. Free shipping is only available within the contiguous United States. Frozen foods, live foods, and items shipped directly from the manufacturer do not qualify for this special offer.
Free Upgraded Shipping For Orders $250+
Most orders over $250 qualify for FREE upgraded shipping! Your order will be delivered 1-5 days after it ships out. Thanks to Marine Depot's two strategically located warehouses in Nevada and Georgia, over 90% of shoppers receive their orders within 1-2 business using this level of service. Orders placed before 10:30 am PST Monday-Friday are shipped the same day. Free shipping is only available within the contiguous United States. Frozen foods, live foods, and items shipped directly from the manufacturer do not qualify for this special offer.
$2.99 Flat Rate Shipping For Orders Under $29
Most orders under $29 ship for only $2.99 using a mix of economy shipping methods including UPS Ground, USPS First Class, and/or SurePost. Your order will be delivered in up to 7 business days after it ships out. Orders placed before 10:30 am PST Monday-Friday are shipped the same day. Our $2.99 flat rate shipping is only available within the contiguous United States. Frozen foods, live foods, and items shipped directly from the manufacturer do not qualify for $2.99 flat rate shipping.
Frozen foods are delivered 1-3 business days from the day your order ships. Frozen foods are shipped every Monday and Tuesday. Shipping cut-off is Tuesday at 10 am PST (1 pm EST). Orders received after 10 am PST on Tuesday will be shipped the following week. Shipping and handling is a $19.99 flat-rate charge so you can order as much or as little as you like.
Orders not shipped within the contiguous United States—the 48 U.S. states on the North American continent south of Canada plus the District of Columbia—are considered international orders. International orders are not eligible for Marine Depot’s free shipping promotions and additional surcharges may apply. It is important to note that not all products we carry can be shipped internationally. Any brokerage fees, tariffs and/or taxes will be billed to you directly by the shipping courier. International customers must use the same billing and shipping address.
Contains calcium, strontium, and magnesium in the same ionic ratios found in aragonite. This unique feature increases the usefulness of Kalk+2 to reef-building invertebrates such as corals, clams, calcareous algae, etc.
Provides temporary alkalinity and helps maintain pH within the desired range when used as directed.
Adds no conservative elements, such as chloride, to the aquarium.
Improves upon the industry-standard powdered calcium supplement over the past three decades.
Formulated by a marine scientist.
Technical Background Calcium, magnesium, and strontium are required for the formation of aragonite, the skeletal material of reef-building invertebrates such as corals, clams, tube worms, and their respective allies. Brightwell Aquatics Kalk+2 provides these elements and may also be used to help regulate pH in reef aquaria. Kalk+2 does not contain chloride salts, which is a strong point for some hobbyists. The use of kalkwasser-type products remains very popular with many seasoned hobbyists, regardless of innovations in calcium-delivery methods.
Instructions and Guidelines Kalk+2 is intended for use by experienced hobbyists who are familiar with kalkwasser (calcium hydroxide-based) products. The calcium concentration (”[Ca2+]”) and pH in the aquarium should be determined by using an accurate test kit prior to supplementing. Do not add this product directly to an aquarium without diluting in water as directed, and do not overdose; it must be added in a controlled fashion with a dosing device. Create a stock solution by dissolving 6 grams (~1 tsp) of Kalk+2 in 1 US-gallon of fresh water (preferably purified) and allowing at least one hour for any settling to occur; each ml of the saturated sol’n will increase the [Ca2+] in 1 US-gallon (3.785 L) of water by 2.3 ppm, strontium concentration by 0.04 ppm, and magnesium concentration by 0.06 ppm. This solution must then be dosed/dripped into the aquarium at such a rate that salinity does not fall below 1.021 g/cm3 and pH does not increase by more than 0.1 every hour, nor is it ever allowed to exceed a value of 8.5. Dosing at night when pH in a reef aquarium is naturally depressed is often performed to avoid exceeding the maximum allowable pH value. If the [Ca2+] in an aquarium is gradually dropping despite using this product as directed, the rate of evaporation may be insufficient or pH may be too high to dose sufficient calcium to compensate for the rate of removal by reef-building aquarium inhabitants and/or undesirable chemical reactions. In this case, a secondary calcium supplement may be needed to occasionally re-establish the natural seawater concentration of calcium in the aquarium.
Caution: Calcium hydroxide is a caustic material; if inhaled, remove to fresh air, and in case of contact flush skin and/or eyes with fresh water for 15 minutes. Drink 16-oz. fruit juice if swallowed and seek immediate medical attention. Keep out of reach of children. Not for human consumption.
Brightwell Aquatics Aquarium Supplies The goal of Brightwell Aquatics is to provide the absolute highest quality, scientifically-sound products and customer service of any aquarium water care manufacturer, and to do it all in a straight-forward and honorable fashion. All Brightwell products are formulated by marine scientists with a passion for the aquarium hobby. They utilize the highest purity ingredients in concentrations that provide the most use to hobbyists. Nearly all Brightwell Aquatics products are over 99.9% pure. The usage guidelines of Brightwell Aquatics products are written in plain language but the company is always available to answer consumer questions. All products are lot numbered for quality control and customer service.
Ask a Question Earn 15 Points when you answer a question
This is a great kalk supplement. I find that it dissolves more readily than other brands of kalk, which is what could make kalk a pain. Another awesome, but off label, usage for this is as aptasia killer. You mix water with the kalk, just enough to make a liquidy paste, and you squirt it into t...Read More
This is a great kalk supplement. I find that it dissolves more readily than other brands of kalk, which is what could make kalk a pain. Another awesome, but off label, usage for this is as aptasia killer. You mix water with the kalk, just enough to make a liquidy paste, and you squirt it into the head/mouth of the aptasia and they close up on it and will die.Hide
This product just looks like expensive lime to me. I tried a jar and it looked and performed like bulk lime. I think it would be really hard to tell if it made any difference.
I have been using this product for about 6 months now. Helps maintain my ph and keep my calcium up. It is much easier than other Kalk waters that need to form multiple layers and then be separated.
Most orders under $29 ship for only $2.99 using a mix of economy shipping methods including UPS Ground, USPS First Class, and/or SurePost. Your order will be delivered in up to 7 business days after it ships out.
free shipping for orders $29+
We ship 99% of the products we carry for free within the contiguous United States using a mix of economy methods including USPS First Class Mail, SurePost and UPS Ground. Your order will arrive in up to 7 business days. Just spend $29 or more!
free faster shipping for orders $250+
Over 90% of shoppers receive their orders within 1-2 business days. Upgrade from free economy shipping to faster shipping for only $2.99—or spend $250 and we'll upgrade you automatically!
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Expedited shipping services are available for most products if you are in a hurry. Get guaranteed delivery in 2 business days, 1 business day, or next day by 10:30 am. Costs vary by location.
buy it today and we'll ship it today
Same-day shipping is available Monday-Friday for most products—place your order by 10:30 am PST. Pre-ordered and back-ordered items do not qualify, nor do drop-shipped, live, or frozen shipments.
live plants, live foods, and frozen foods delivered to your door
We ship live plants, live foods, and frozen foods within the contiguous United States. Each of these categories is subject to its own $19.99 flat-rate shipping fee to cover the special packaging and/or expedited shipping costs required to ensure safe delivery. Orders with 12+ live plants ship free!
Return any new and unused item within 60 days for a full refund. Having difficulty with a product? Contact us to speak with an aquarium expert. If you need a replacement, fill out this form.
A small segment of the 180+ brands we carry require that customers contact them directly if/when problems arise. You can view the full list of those brands and get their contact info here.
We are unable to accept returns of Digital Aquatics, Neptune Systems, Vertex Aquaristik, Aqua Illumination (AI), EcoTech Marine, GHL, or Seneye products once the manufacturer's packaging seals have been broken.
Marine Depot is an authorized reseller for every product we carry. That means when you buy aquarium supplies from us, your products are not only backed by our own 60-day return policy, they also carry full factory warranties, where applicable. Some items have a 1-year warranty, others have limited lifetime warranties. Warranty coverage varies from manufacturer to manufacturer, so please read the product description of the item(s) you are considering thoroughly for details or contact us if you have warranty questions.
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