One of the best places to be during #99DaysofSummer is poolside. The sweet relief from the blazing heat that you get by diving into a cool body of water is always a good time (not to mention a pretty fast route to beachy waves, too). The only downside? Depending on what type of water you’re submerging yourself in, you could be taking a toll on your complexion.

As you could imagine, chlorine isn’t exactly your skin’s BFF. “Chlorine’s a strong antibacterial used in pools to prevent overgrowth of harmful bacteria,” says Dr. Loretta Ciraldo, MD, FAAD, a board-certified dermatologist and co-founder of her eponymous skin-care line. “But it can be problematic to skin since it binds to it and is difficult to wash off.” That tight feeling you get after a dip? You’re not imagining it: “Chlorine can cause dryness and irritation, and give rise to free radical damage,” says Dr. Ciraldo. And that can lead to the formation of things like fine lines and acne.

This isn’t always the case when you’re in a pool, but she explains that chlorine can be more damaging in three key instances. For starters, the chemical can be aggravating when the ratio of chlorine to water skews high, so check the concentration levels of chlorine before you take a dip, if possible. Second, when you’re swimming on the reg, you obviously increase your exposure and up the risk of a reaction. Finally, when your skin barrier is already compromised; for instance, you have a condition such as eczema, tend to be sensitive, or have frequent allergic reactions on skin, chlorine can further irritate skin.

“Chlorine can cause dryness and irritation, and give rise to free radical damage.”

But by being prepared, you can help temper the effects: Myriam Zaoui Malka, co-founder of Dr. Loretta skin care and holistic medicine expert, advises to apply a very thin coat of organic coconut oil to your skin at least an hour before you go in the pool to act as a barrier to prevent chlorine binding to skin. Of course, you should top that with a sunscreen of course to prevent harmful rays and keep the sun burn far, far away.

Afterwards, Malka says to hop in the shower ASAP. “Since chlorine’s very adherent to skin, it doesn’t simply wash away with water and regular soap, so shower within ten minutes of leaving the pool.” Follow that with a free radical fighter, she says such as vitamin C, which “has been shown to combat the free radical damage that’s associated with chlorine exposure.” And since chlorine can be dehydrating to skin, it’s also good to slather on a hydrating mask, to rejuvenate skin post-pool, Spa Radiance facialist Angelina Umansky adds.

“The therapeutic effects of bathing in mineral-rich waters has been known for ages.”

When you go into the ocean, on the other hand, it’s a completely different  story. As you would probably guess, saltwater’s not as bad for you—in fact, it can have some major benefits. “Saltwater actually helps with acne because it sterilizes the skin,” says Umansky, who adds that you want to swim makeup free in the ocean to reap all the benefits. Dr. Ciraldo says that it’s so helpful because it’s full of many vitamins, amino acids, and minerals like magnesium, potassium, and sulfur. “Because of this, saltwater’s been shown to lessen some of the mediators of skin inflammation,” she says. “The therapeutic effects of bathing in mineral-rich waters has been known for ages.”

But there’s too much of a good thing—they both note that saltwater can be drying. “As soon as you’re home from the beach, take a shower in tepid water and use a non-soap moisturizing cleanser,” says Dr. Ciraldo. “Then apply concentrated moisturizing products to skin while it is still damp.” To protect yourself from dryness before an ocean dip, she advises to use a reef-safe, water-resistant sunscreen with zinc oxide or titanium dioxide as the active ingredients. “This type’s formulated to use heavier emollients so it creates a protective barrier over the skin so the water doesn’t penetrate as deep and disrupt the skin’s natural moisture barrier.”

And now back to your regularly #99DaysofSummer programming: *Splash.*

To stay protected as you do so, these are the best moisturizing face sunscreens (with no chalkiness in sight)—and *this* is how much sunscreen you actually need, according to a dermatologist.